[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.

[gemini-code-assist]

The force unwrap operator (!) on the result of getCameraCharacteristic could lead to a runtime crash if the characteristic is not available on the device and the method returns null. It's safer to handle the potential null value, for example by defaulting to an empty list.

Suggested change

	final List<int> controlModes =
	(await camera2CameraInfo.getCameraCharacteristic(
	CameraCharacteristics.controlAvailableVideoStabilizationModes,
	))!
	as List<int>;
	final List<int> controlModes =
	await camera2CameraInfo.getCameraCharacteristic(
	CameraCharacteristics.controlAvailableVideoStabilizationModes,
	) as List<int>? ??
	const <int>[];