Mention UHID permission errors

UHID may not work on old Android versions due to permission errors.

Mention it in UHID mouse and gamepad documentation (it was already
mentioned for UHID keyboard).

Refs #4473 comment <https://github.com/Genymobile/scrcpy/pull/4473#issuecomment-1975133226>
PR #5270 <https://github.com/Genymobile/scrcpy/pull/5270>