Updated flutter/examples to further conform to new embedding: removed references to FlutterApplication, deleted all MainActivity's that were not necessary, removed all direct invocations of GeneratedPluginRegistrant. (#22529) (#44782)

* Canonicalize locale string for gen_l10n.dart script

* Refresh stocks example to use canonicalized locale

* Sort locales and method/properties/getters alphabetically

* Refresh stocks example to show proper sorting

* Add check for placeholders being an empty map

* Remove unnecessary properties from en_ES.arb in the stocks example

* Use getter instead of methods in the stocks example

* Fixed "annotating types for function expression parameters" lint issue from generated localizations delegate code

* Use raw string for l10n description

* Stock app refresh

* Add pubspec.yaml comment

* Add --help flag

* Use l10n tool to generate stocks i18n files

* Rename *_en_EN.arb to *_en_US.arb

* Fix l10n script

This reverts commit 99cd4403.

This reverts commit 46edc802.

* Fix device lab tests

* Migrate examples to the Android embedding v2 (#43221)

* [flutter_tool] Use engine flutter_runner prebuilts

* Update packages/flutter_tools/lib/src/fuchsia/fuchsia_build.dart
Co-Authored-By: Jonah Williams <jonahwilliams@google.com>

This reverts commit b49ffa81.

Revert "replace package:vm_service_client with package:vm_service in the devicelab project (#41646)" (#41960)

* WIP on web plugin registry

* WIP on registering plugins

* WIP on web plugin registration

* Only generate `package:flutter_web_plugins` imports if plugins are
defined

* Add parsing test

* Add documentation

* Fix analyzer warnings

* add license headers

* Add tests for package:flutter_web_plugins

* Run `flutter update-packages --force-upgrade`

* Fix analyzer errors

* Fix analyzer error in test

* Update copyright and remove flutter SDK constraints

* Enable tests since engine has rolled

* add flutter_web_plugins tests to bots

* Create an empty .packages file for WebFs test

This fixes a breakage in fuchsia where package_config version 1.1.0 is
required but flutter_tools is currently locked to 1.05.