UX: Room type restrict usage role select / Role select behaviour

[Sabr1n4W]

Problem
Currently the restrict usage role select of the room type settings requires at least one role to always be selected after a role was selected. Because of this it is not possible to clear the role select after adding a role to it.
Also if a user selected a wrong role it is necessary to add another role before it is possible to remove the wrong role from the role select.
Additional to this the role select does not get cleared when deactivating and reactivating the restrict usage setting.

Possible solution
Clear the role select when deactivating the role select. Especially if the settings are saved in between.

(This solution could also have disadvantages because the role selection would be lost if a user accidentally deactivates the restrict usage setting)

Alternative solution
Allow clearing the role select by deleting all selected roles (even if only one role is selected)

(When applying this solution it should be checked if this behaviour should also be added to some of the other role selects)