[camera_android_camerax] Pass targetVideoEncodingBitRate to Recorder

[Anantha-Eswar]

This PR fixes an issue where the videoBitrate parameter configured in MediaSettings was ignored during video recording on Android using CameraX.

We now forward mediaSettings?.videoBitrate as the targetVideoEncodingBitRate when instantiating the CameraX Recorder instance in AndroidCameraCameraX.createCameraWithSettings.

Fixes flutter/flutter#179832

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[gemini-code-assist]

Code Review

This pull request updates the camera_android_camerax package to version 0.7.3, fixing an issue where the videoBitrate configuration was ignored during video recording. The Recorder is now instantiated with targetVideoEncodingBitRate mapped from mediaSettings?.videoBitrate, and unit tests have been updated to verify this configuration. There are no review comments, and I have no feedback to provide.