[3.3.x] video player: respect gesture options in the user sense

Users do not differentiate between the slider and the gesture offered by the player interface. If the gesture is disabled, so should be the visual control that is also manipulated with a gesture.

Additionally, this fixes the slider background of the opposite slider to appear on animation if either the volume or the brightness gesture is disabled.

(cherry picked from commit 1754412e, backport of !688 (merged))