This reverts commit d3ee5ace.

Resolved contradictory documentation of showGeneralDialog and default value of 'barrierLabel' argument (#78890)

[flutter_tools] migrate tool_backend.dart to null safety and add testing of exit conditions (#78988)

Add ability to control RefreshProgressIndicator's distance from edges.

This reverts commit 8caf4d44.

This reverts commit 515ef91b.

This reverts commit a2f5b18e.

- Remove `LogicalKeyboardKey.keyLabel`
- Make `Physical/LogicalKeyboardKey.debugName` getters
- Make `Physical/LogicalKeyboardKey()` factory constructors, which cache non-predefined instances.

* Remove need for unused import for placeholder braces

* Remove need for unused intl import for when plurals aren't used in the generated code

* Add dismiss action to modal barrier

* fix test

* fix another test