VideoCaptureTest.kt is built even when MOZ_WEBRTC is false

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/VideoCaptureTest.kt is a test for WebRTC.

It seems to be always built in 128, and this makes our build fail.

The quick&dirty workaround is to delete the file, but I'm sure we could do something to disable it in config and uplift the patch.