[camera] Add support for RGBA_8888 image streaming format

[Mairramer]

This PR adds support for the rgba8888 image format group for both Android (camera_android_camerax) and iOS (camera_avfoundation).

Closes flutter/flutter#151193

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[Mairramer]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces support for the rgba8888 image format across the camera plugin ecosystem, covering the platform interface, Android (CameraX), and iOS (AVFoundation) implementations. The changes include necessary enum additions, mapping logic, Pigeon-generated code updates, and unit tests. Review feedback identifies missing mappings for the Android PixelFormat.RGBA_8888 constant (value 1) in the main package and platform interface. Furthermore, updates to dependency versions in several pubspec.yaml files are required to ensure cross-package compatibility for the new format.

[Mairramer]

/gemini review

[gemini-code-assist]

Code Review

This pull request adds support for the rgba8888 image format across the camera plugin and its federated implementations for Android (CameraX) and iOS (AVFoundation). The changes include updating the platform interface, adding format mappings in the native implementations, and bumping package versions. Feedback was provided regarding a potential mismatch in Android format codes where PixelFormat.RGBA_8888 (1) should be supported alongside ImageFormat.FLEX_RGBA_8888 (42) for consistency, and a minor documentation fix was suggested for a constant name.

[gemini-code-assist]

Code Review

This pull request adds support for the rgba8888 image format across the camera plugin ecosystem, including the platform interface, Android (CameraX), and iOS (AVFoundation) implementations. The changes include updating the ImageFormatGroup enum, implementing format mapping logic in Dart and native code, and adding corresponding unit tests. Additionally, Pigeon-generated files were updated to a newer version, and temporary dependency overrides were included for testing. I have no feedback to provide.