Forward video constraints to subclasses directly

Make the abstract superclass `SurfaceCapture` forward the
`VideoConstraints` instance directly via the `init()` method, instead of
storing it and exposing it via `getVideoConstraints().

This will let implementations handle it as they wish, particularly with
regard to synchronization.

PR #6772 <https://github.com/Genymobile/scrcpy/pull/6772>