fix(player): retry mounting video stats icon until DOM is ready

[dcmclarke]

Proposed changes

Resolves #979

When the Video Stats setting is enabled, the stats icon wouldn't show up again after a page reload until the setting was manually toggled off and on. Reported issue since December 2023.

Root cause is a timing problem, remount() was called once on mount, but at that point Twitch's DOM isn't fully ready yet and span.live-time doesn't exist. Fix replaces the single call with a retry loop (tryMount) checking for the element every 500ms, up to 10 attempts (5 seconds total). Once the element is found, remount() called successfully.

Tested: video stats icon appears automatically on page load without needing to toggle the setting.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged