Remove unused `redirect_to_external_issue_tracker` method
What does this MR do?
It removes unused redirect_to_external_issue_tracker method.
Its usage has been removed at 2fa22a07.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
It removes unused redirect_to_external_issue_tracker method.
Its usage has been removed at 2fa22a07.