[camera_web] Fix camera initialization failure on Firefox Android (#10341)
## Description
Fixes camera initialization failure on Firefox Android when no video constraints are specified.
Firefox Android rejects getUserMedia({video: {}}) with an AbortError, but accepts {video: true}. This PR modifies VideoConstraints.toMediaStreamConstraints() to return true.toJS instead of an empty object when no constraints are specified, improving browser compatibility.
## Related Issue
This fix addresses camera initialization failures on Firefox Android where the camera plugin would fail with a CameraException(cameraAbort) error.
Fixes https://github.com/flutter/flutter/issues/115892
## Testing
Tested on Firefox Android with camera initialization - camera now successfully initializes where it previously failed.
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Remove "All right reserved" from all files (#10066)
Per guidance from legal on current preferred practice, remove "All rights reserved" from all LICENSE files and header blocks, and update the repo tool check accordingly.