Adjust media control positioning if video aspect ratio is maintained

[rh101]

Describe your changes

This is to ensure the controls are within the video player boundary when videoPlayer->setKeepAspectRatioEnabled(true) is set.

Issue ticket number and link

Checklist before requesting a review

For each PR

• [ ] Add Copyright if it missed:
  • "Copyright (c) 2019-present Axmol Engine contributors (see AUTHORS.md)."

• [ ] I have performed a self-review of my code.

  Optional:

  • [ ] I have checked readme and add important infos to this PR.
  • [ ] I have added/adapted some tests too.

For core/new feature PR

• [ ] I have checked readme and add important infos to this PR.
• [ ] I have added thorough tests.