Display if HotCorner action is assigned to the corner

[zahhar]

By default there are some actions can be assigned to corners using MacOS built-in feature HotCorners. In this case collision happens between HottestCorners and HotCorners, that needs to be resolved.

Ideally, setting HottestCorners action must clear HotCorners action. If this is not possible, then HottestCorners should detect if HotCorner action is already assigned to particular corner, and in this case do not allow users to assign any action in HottestCorners, but navigate them to Settings where they should clear the action.