test: Add WebKit to interop tests

[p-shahi]

Work is being done to add WebKit to interop tests here #1799 however per #2007 this effort is currently blocked

[dhuseby]

Webkit still doesn't have full support for WebRTC. Until then, this is blocked.

[SgtPooki]

JS Colo 2024 discussion

we need a PR to test this so we know when things are actually unblocked without needing a lot of manual interaction

Action item

1. get out draft PR for adding webkit to test runner

[maschad]

@SgtPooki isn't that the purpose of #2541 ?