SIMPLIFY: unlocked_database.database_manager.get_group_uuid_from_group_object()

Instead of writing: group_uuid = self.unlocked_database.database_manager.get_group_uuid_from_group_object(self.unlocked_database.current_group) we can do: group_uuid = self.unlocked_database.current_group.uuid

Confusingly current_group can ALSO be an entry! (it denotes the object of the currently visible stack page), and the code had to lots of check for whether current_group is a Group or an Entry, and used different functions to get the uuid. By simply using *.uuid which works for both Entry and Group objects we can simplify the code and take out quite a lot of IFs.