[43] overview: Handle unredirection in OverviewShown state machine

Under certain unknown circumstances currently not every disable_unredirect_for_display() gets matched with an enable_unredirect_for_display() when closing the overview.

As we only want to not disable unredirection when hidden and we nowadays have a state machine that ensures we transition to and from one state to another only once, handle unredirection en-/disablement as part of the state transition.

Part-of: !2970 (merged)

(cherry picked from commit a94fcee9)