## Description

This PR introduces `DefaultSelectionStyle.mouseCursor` to configure the mouse cursor over selectable text.
It also applies this solution to `InkResponse` to make the mouse cursor win over the default one provided by selectable `Text` for many Material components (such as buttons). 

### Before

https://user-images.githubusercontent.com/840911/233627729-ddf98e2a-444d-4c6d-a6d5-f521982f48dd.mov

### After

https://user-images.githubusercontent.com/840911/233627718-8871a68f-d33c-44cf-b4a1-91bb1fcdf076.mov

## Related Issue

Fixes https://github.com/flutter/flutter/issues/104595

## Tests

Adds 6 tests.

Add one DefaultTextStyle example

* dart fix --apply

* manual fixes

* Use `curly_braces_in_flow_control_structures` for `widgets`

* fix comments

* fix comments

* Support global selection

* addressing comments

* add new test

* Addressing review comments

* update

* addressing comments

* addressing comments

* Addressing comments

* fix build

* fix deprecated_new_in_comment_reference for `material` library

in a future version of the SDK, these will be flagged, fix them now

* Update pubspec.yaml

* add `semanticsLabel` to `SelectableText`

* remove unused vars

* Squashed commit of the following:

commit 3e687a9f
Author: engine-flutter-autoroll <engine-flutter-autoroll@skia.org>
Date:   Tue Sep 14 17:42:05 2021 -0400

    Roll Plugins from 4a98e239b131 to b85edebe7134 (2 revisions) (#90083)

commit ad936b4e
Author: Christopher Fujino <christopherfujino@gmail.com>
Date:   Tue Sep 14 14:39:17 2021 -0700

    [flutter_conductor] Support initial stable release version (#89775)

commit ff5dd54c
Author: Ian Hickson <ian@hixie.ch>
Date:   Tue Sep 14 13:02:04 2021 -0700

    Mention the ToS on our README (#89765)

commit 8587b609
Author: Kate Lovett <katelovett@google.com>
Date:   Tue Sep 14 14:53:33 2021 -0500

    Update local gold api (#90072)

commit 7d368dcf
Author: Justin McCandless <jmccandless@google.com>
Date:   Tue Sep 14 12:39:19 2021 -0700

    InteractiveViewer with a child of zero size (#90012)

    Asserts that the InteractiveViewer child can't have zero size.

commit 2b4ef184
Author: Akira Aratani <developer.a.akira@gmail.com>
Date:   Wed Sep 15 03:30:50 2021 +0900

    Fix document of the switch. (#89641)

commit a2cd16ba
Author: Christopher Fujino <christopherfujino@gmail.com>
Date:   Tue Sep 14 11:22:02 2021 -0700

    use test logger, which does not allow colors (#90010)

commit 0f0613c0
Author: Varun Sharma <varunsh@stepsecurity.io>
Date:   Tue Sep 14 11:17:03 2021 -0700

    Add specific permissions to .github/workflows/lock.yaml (#89820)

commit 2866f79c
Author: Jason Simmons <jason-simmons@users.noreply.github.com>
Date:   Tue Sep 14 10:46:35 2021 -0700

    Initialize all bindings before starting the text_editing_action_target test suite (#90067)

    Fixes https://github.com/flutter/flutter/issues/90057

commit b8899159
Author: Michael Thomsen <mit@google.com>
Date:   Tue Sep 14 14:08:36 2021 +0200

    Change min Dart SDK constraint to track actual version (#88743)

commit 3b7adb98
Author: godofredoc <54371434+godofredoc@users.noreply.github.com>
Date:   Mon Sep 13 21:32:04 2021 -0700

    Lock only issues. (#90023)

commit 528f77dc
Author: Dan Field <dnfield@google.com>
Date:   Mon Sep 13 19:10:15 2021 -0700

    Opacity fix (#90017)

    * Make sure Opacity widgets/layers do not drop the offset

commit 2470f63e
Author: engine-flutter-autoroll <engine-flutter-autoroll@skia.org>
Date:   Mon Sep 13 22:07:02 2021 -0400

    4a98e239b [flutter_plugin_tools] Make no unit tests fatal for iOS/macOS (flutter/plugins#4341) (#90016)

commit a01e4733
Author: stuartmorgan <stuartmorgan@google.com>
Date:   Mon Sep 13 20:57:05 2021 -0400

    Re-enable plugin analysis test (#89856)

commit cdad35f2
Author: Aneesh Rao <sidrao2006@gmail.com>
Date:   Tue Sep 14 05:17:04 2021 +0530

    Fix path in example (#84707)

commit 576aab08
Author: Christopher Fujino <christopherfujino@gmail.com>
Date:   Mon Sep 13 15:47:03 2021 -0700

    add analysis_options.yaml to dev/conductor (#90005)

commit fad5e4cf
Author: Jason Simmons <jason-simmons@users.noreply.github.com>
Date:   Mon Sep 13 13:37:07 2021 -0700

    Remove a redundant test case in the flutter_tools create_test (#89872)

commit 738430ca
Author: Darren Austin <darrenaustin@google.com>
Date:   Mon Sep 13 13:33:48 2021 -0700

    Revert "Removed default page transitions for desktop and web platforms. (#82596)" (#89997)

    This reverts commit 43e31977

commit 9db9256b
Author: Dan Field <dnfield@google.com>
Date:   Mon Sep 13 13:15:19 2021 -0700

    Revert "Make sure Opacity widgets/layers do not drop the offset (#89264)" (#89999)

    This reverts commit 0d0f7a4f.

commit 00f78cf2
Author: keyonghan <54558023+keyonghan@users.noreply.github.com>
Date:   Mon Sep 13 13:04:01 2021 -0700

    renew cirrus key (#89988)

commit 826da7f8
Author: engine-flutter-autoroll <engine-flutter-autoroll@skia.org>
Date:   Mon Sep 13 15:52:03 2021 -0400

    cfc8a20a1 renew cirrus key (flutter/plugins#4340) (#89996)

commit cd112e55
Author: Anna Gringauze <annagrin@google.com>
Date:   Mon Sep 13 12:13:42 2021 -0700

    Update all packages (#89797)

Update samples to use repo analysis options, Fix sample templates and a ton of analyzer issues (#77868)

* migrate material to nullsafety

* address review comments

* address review comments

* fix build

* Reland "Nnbd widgets (#64672)"

This reverts commit 127e6790.

* remove non-nullable enforcement on AsyncSnapshot

* make data param non-nullable for AsyncSnapshot.withData

* make some Text params non-nullable

This reverts commit e682ec71.

* migrate widget to nullsafety

* remove double blank line after license

* address review comments in actions.dart

* nullable ObjectKey.value

* use local variable oldElement

* make State.build non-nullable

* make State.context non-nullable

* newline at eof

* make ProxyWidget.child non-nullable

* make _InactiveElements.debugContains non-nullable

* make Element.depth non-nullable

* make ProxyElement.build non-nullable

* make StatefulElement.state non-nullable

* remove 'Notice that'

* avoid cast of list in RenderObjectElement.updateChildren

* make IndexedSlot.value non-nullable

* avoid cast of list in MultiChildRenderObjectElement.mount

* make some WidgetsApp parameters non-nullable

* hitTest take non-nullable position

* make ScrollableState.position non-nullable

* use _pixels instead of pixels

* make ViewportOffset.pixels non-nullable

* make param and return type of IndexedWidgetBuilder non-nullable

* unused_import

* make context param non-nullable for Builder in animated_list.dart

* make ScrollMetrics.viewportDimension non-nullable

* make ScrollMetrics.{min,max}ScrollExtent non-nullable

* make _Location.file non-nullable

* _WidgetForTypeTests.createElement throw UnimplementedError

* update _NullWidget.build error message

* make _ShortcutsState.manager non-nullable

* Fix childCount issues for NNBD

* fix childCount computation on web

* increase max value on js side to compute childCount

* make aspect parameter of dependOnInheritedWidgetOfExactType nullable

* merge has{min,max}ScrollExtent into hasScrollExtents

* update focus_manager.dart

* address review comments in icon.dart

* address review comments in image.dart

* address review comments in routes.dart

* address review comments in scroll_activity.dart

* update doc comments

* make UserScrollNotification.direction non-nullable and required

* rename hasScrollExtents to hasContentDimensions

* unnecessary late
Co-authored-by: Ian Hickson <ian@hixie.ch>

I modified TextAlign docs because the descriptions of TextAlign.center and Center Widget are so similar that they cause confusion.

Fixes https://github.com/flutter/flutter/issues/5805

This reverts commit 561735ad.

Updated references to the old button classes to the new ones in comments and documentation for classes in the widgets, services and rendering libraries. (#62099)

This reverts commit c816fabd.

This reverts commit 3efc517a.