Half-transparent webm videos are not rendered correctly in Chrome.

**mapbox-gl-js version**: 2.14.1

**browser**: Chrome 112.0.5615.49

### Steps to Trigger Behavior

1. Add a [video](https://github.com/SiggyF/mapbox-gl-js/blob/fix/alpha-video-test/debug/testbeeld.webm) with an alpha channel and add it as a video source in debug folder.
2. [Change](https://github.com/SiggyF/mapbox-gl-js/commit/c0ae2d97eb0250033ac05320b44bc58af9dcd317) the video source of the test video to the test video.

### Link to Demonstration

https://codepen.io/SiggyF/pen/jOeqRZO

### Expected Behavior
Video should show aliased transparent circles. All colored rectangles should be half transparent
### Actual Behavior
Video shows inconsistent transparency (black colours are transparent, white is opaque). Transparency flickers while moving (both in Firefox as in Chrome).

It might be related to #2216, which was a browser issue.

## Incorrect display in Chrome

- Green rectangles are too opaque
- White circle is opaque and not aliased

## Correct display in Firefox (while not moving)

- All colored rectangles are half transparent
- White circle is half-transparent and aliased

Start by reproducing the issue with the alpha-channel video described in the debug folder and compare the CodePen behavior in Chrome and Firefox. Trace the video-source rendering path from that reproduction, then verify that transparent colors and anti-aliased edges render consistently without flickering in the affected browsers.

Written by the indexing model from the issue text.