fix: groups join fails due to timeout or broken selector (#594)

[sigvardt]

Summary

Fixes #594

Changes

• Updated joinRegex to match both "Join" and "Request to join", along with Danish translations.
• Added a pre-flight check to see if the Join button is visible before attempting to click. If not, it checks whether the user is already joined or has already requested to join and returns successfully if so, otherwise it throws a clear UI_CHANGED_SELECTOR_FAILED error.
• Updated waitForCondition to explicitly watch for any dialog surface appearing (e.g. questions or additional confirmation modals).
• If a dialog appears, it attempts to dismiss it (to avoid state bleeding) and then throws an ACTION_PRECONDITION_FAILED explaining that questions/confirmation is required to join.

Closes #594