Skip collapsed tab groups when navigating with J/K

[tusharmurali]

Chrome's native tab navigation (Ctrl+Tab) skips over collapsed tab groups - you can only navigate to visible tabs. Vimium's J/K currently navigates into collapsed groups, which feels inconsistent.

I have a working implementation locally that makes J/K skip collapsed groups (using the tabGroups API). Before submitting a PR, I wanted to check:

1. Is this desired behavior? Or do some users prefer being able to navigate into collapsed groups?
2. Should it be configurable? e.g., a setting or command option like map K nextTab skipCollapsed
3. Are tests needed? The change is ~25 lines and affects nextTab/previousTab/firstTab/lastTab.

Note: This would add the tabGroups permission (no new user-facing warnings). Firefox behavior would be unchanged since it doesn't support tab groups.

Happy to submit a PR if there's interest.

[imsodin]

Unless I misunderstand (quite possible), this looks like a duplicate of: Support for jump over tab groups #4693 - @tusharmurali is it?