Video player toolbar button sizes are too small on mobile

Toolbar buttons in the video player are currently 30x30px on mobile. They should be 44px per [our own](https://github.com/hypothesis/frontend-shared/blob/b028ea0041ac06e726e571012483431c6d5cd077/src/tailwind.preset.js#L8) + Apple's guidelines.

<img width="321" alt="Video player iOS toolbar button size" src="https://github.com/hypothesis/via/assets/2458/a90193b4-5b8c-4892-a873-135b26968712">
