Jonny Wang 8a83072ebc A11y enabled state (flutter/engine#48653)
Sets enabled state in Fuchsia a11y via the accessibility bridge.

This was added in Fuchsia API v15, which Flutter is updated to use after
#48233.

b/261482081

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I added new tests to check the change I am making or feature I am
adding, or the PR is [test-exempt]. See [testing the engine] for
instructions on writing and running engine tests.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I signed the [CLA].
- [x] All existing and new tests are passing.
2023-12-05 18:17:28 +00:00
Languages
Dart 75%
C++ 16.5%
Objective-C++ 2.9%
Java 2.8%
Objective-C 0.7%
Other 1.9%