fix(kick): update username element selector after changing Kick UI

[dcmclarke]

Proposed changes

Resolves #1219

Kick changed their UI and removed the title attribute from username buttons in chat. 7TV's chat observer was using button[title] to find the username element which silently failed after this change so emotes did not render in Kick chat.

Fix updates the selector from button[title] to button.font-bold to match Kick's current markup.

Tested: 7TV emotes now render correctly in Kick chat with the updated selector.

Note: Workaround userscript posted in the issue by reporter but this fix addresses root cause directly in codebase.

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