[Accessibility] In media viewer, make caption controls accessible on the same level of interaction as primary media controls #6463

Describe the bug

The caption on/off control is located within a secondary menu accessed through the player's three-dot menu, whereas primary media controls (play, pause, and volume) are directly accessible on the player. Activating captions therefore requires an additional interaction step compared with using the primary controls. Consider making the caption control directly accessible at the same interaction level as the primary media controls.

To Reproduce

Steps to reproduce the behavior:

1. Upload a video along with a transcript (.vtt) to enable captions
2. Click on three-dot menu to access caption toggle (on/off)

Expected behavior

The caption toggle should be at the same level of interaction as the primary controls, such as play, pause, and volume control.

Related work

This may be related to #6460 and #6461, if moving to a more accessibility-friendly embedded player is an option.