The difference between this PR and the original is the change to the `AndroidManifest.xml`. For context, right before the original PR landed, [a change to upgrade the target sdk](https://github.com/flutter/engine/pull/47683) in the manifest from 31 to 33 landed. It also removed the lint complaining about using an old target sdk version from the baseline lint file. So this change upgrading the sdk, but not the target sdk in the manifest, triggered the lint again.
For the rest of the PR, [see the description of the original PR](https://github.com/flutter/engine/pull/47609).
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
## Description
This Android related PR adds a channel buffer and a plugin to interact with Android 'process text' feature. It makes it possible to query text processing actions and to run those actions (for instance 'calling' Google translate).
Text actions that outputs a processed text are supported.
The implementation is based on the great sample provided by @gualse , see https://github.com/flutter/flutter/issues/107603#issuecomment-1646629158.
In order to return a non empty list of text actions, the implementation will require adding a section to the Android manifest file (see https://github.com/flutter/flutter/issues/107603#issuecomment-1683487087).
Adding this section automatically to new or existing Flutter apps is not part of this PR but will be tackled in a future PR.
## Related Issue
Android engine side for https://github.com/flutter/flutter/issues/107603
## Tests
Adds 3 tests.
* Namespaces have been updated to reflect the move from //flutter/sky/shell to //flutter/shell.
* shell/BUILD.gn file has been split into smaller GN files for each subcomponent of the shell (common, GPU, diagnostic, testing).
* GN dependencies have been rewritten to stop exposing common shell dependencies as public. Duplicates have also been removed.
* GPU subcomponent has been updated make it more suitable for Vulkan integration.
* The GLFW backend has been resurrected.
