[camera_android_camerax] Adds support for video stabilization

[ruicraveiro]

Implements getSupportedVideoStabilizationModes() and setVideoStabilizationMode() methods in AndroidCameraCameraX.

Address issue flutter/flutter#89525.
It is the camera_android_camerax sub-PR for #7108.

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[gemini-code-assist]

Code Review

This pull request adds support for video stabilization to the camera_android_camerax plugin. It introduces getSupportedVideoStabilizationModes() and setVideoStabilizationMode() methods. The implementation leverages CameraX's CONTROL_AVAILABLE_VIDEO_STABILIZATION_MODES and CONTROL_VIDEO_STABILIZATION_MODE characteristics. The supported modes are currently mapped to off and level1 (for ON). The changes include updates to Pigeon definitions, native Java/Kotlin code, Dart implementation, and tests to verify the new functionality.

[camsim99]

LGTM just two nits!