[camera_android_camerax] Updates pigeon generation to prevent crash when objects call to Dart after a hot restart

[bparrishMines]

Fixes flutter/flutter#176451

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Code Review

This pull request fixes a crash that occurs when native objects call to Dart after a hot restart. The fix involves updating the pigeon dependency and regenerating the CameraXLibrary.g.kt file. The new generated code correctly adds checks to verify the existence of native instances before making callbacks to Dart. The CHANGELOG.md and pubspec.yaml files are also updated appropriately.

The code changes are correct, but the pull request does not fully adhere to the repository's contribution guidelines. Please update the pull request title to [camera_android_camerax] fix crash and fill out the PR description, including the checklist and a link to the issue this PR resolves.

[camsim99]

This LGTM but just to clarify--does this fix:

This scenario still causes a crash because the callback is being made by a listener attached to a static object. So the listener never gets garbage collected and continues to call to Dart forever.

I'm unclear on what static object you're referring to which is part of my confusion I'm sure 😅

of if that still requires more work.

[bparrishMines]

I believe the Observer is transitively attached to the ProcessCameraProvider.getInstance() static object:

final ProcessCameraProvider provider = ProcessCameraProvider.getInstance();
List<CameraInfo> cameraInfos = provider.getAvailableCameraInfos();
LiveData<CameraState> cameraState = cameraInfos[0].getCameraState();
cameraState.observe(/**add observer **/);

As you stated in #10529, we should remove the observers, but hot restart doesn't give us the chance.

[camsim99]

Ah gotcha okay. So to clarify, throwing the CameraXError prevents the crash?

[bparrishMines]

Yea, returning the CameraXError prevents the crash happening in the codec later and the error is now handled and logged in FlutterMethodRunnable.onFailure.