Use Dart's characters package to fix user-facing grapheme cluster bugs.

Re-land "Deprecate WhitelistingTextInputFormatter and BlacklistingTextInputFormatter (#59120)" (#59876)

This relands #59120, which was reverted in #59870.

Revert "Deprecate WhitelistingTextInputFormatter and BlacklistingTextInputFormatter (#59120)" (#59870)

This reverts commit 8665e138.

This reverts commit e0ed12c7.

This reverts commit b3c237ce.

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

[web & desktop] Hide all characters in a TextField, when obscureText is true on web & desktop (#56794)

* Adds default cursor and/or mouseCursor property to a number of widgets.
* Adds `MaterialStateMouseCurrsor`.

This adds a new navigationMode to the MediaQueryData that indicates how focusable controls should behave under different navigation modes, currently with two modes: NavigationMode.traditional, and NavigationMode.directional.

It may seem like focusing a disabled control is not desirable, but this is useful for user interfaces that use DPAD navigation because if a control gets disabled, losing focus is disruptive to the user, and it is difficult to control where the focus will end up unless it is done explicitly.

This reverts commit 8de07d55.

This reverts commit d9882263.

Unrevert of paste button hides when nothing to paste

This reverts commit d5634982.

Unreverts #54902 with fixes for a failing integration test.

This reverts commit 053c3881.

Adds the ability for the iOS text selection menu to handle items that are too wide for the screen.

* replace simple Container(w & h) with SizedBox

* address review comments

* address review comments

TextFields now disallow adding characters in the center of the text at maxLength.

Adds an overflow menu to the text selection menu on Android when the items overflow.

This PR adds the linux and windows target platform enum values, along with automatically setting the defaultTargetPlatform to the appropriate value on those platforms.

Fixes #31366

Use strut box heights to calculate selection rectangles in order to ensure that they remain within visible bounds (#50354)

Fix tests that rely on FadeTransition incorrectly and depend on implementation details of FadeUpwardsTransitionBuilder (#51150)