Making sure window inset controller is not null

In some cases the controller can be null if the view is no longer
connected to the window.

Also, this issue seems to only happen in cuttlefish instances so there
might be a weird behaviour going on there but in any case is good to check
for nulls.

Test: No testing require is only null checkin, just making sure it compiles.
Bug: 302869930
Change-Id: I88d6091b57293e9493385185bfeb3e470c9bad84