Fix WebGL renderer failing to display video

[Wumpf]

What

• Fixes Fix web VideoDecoder on Chromium/WebGL #7328

This is obviously a brittle hack, but allows us to move on without having to wait on a wgpu release containing gfx-rs/wgpu#6170 :)

Tested using pixi run rerun-web /Users/andreas/Desktop/sample\ videos/Big_Buck_Bunny_720_10s_30MB_av1.mp4 (insert video of your choice) and then running http://localhost:9090/?url=ws%3A%2F%2Flocalhost%3A9877&renderer=webgl in Chrome (on Mac. shouldn't matter much as long as the browser has webcodec support and draws video)

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

• PR Build Summary
• Recent benchmark results
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To run all checks from main, comment on the PR with @rerun-bot full-check.

[jprochazk]

We love more hacks! LGTM: