window: Don't try to focus unmanaging windows

GNOME/mutter!307
3 jobs for !307 with workspace-use-focusable-ancestor in 4 minutes and 12 seconds
detached
Status Job ID Name Coverage
  Review
passed #289055
check-commit-log

00:00:23

 
  Build
passed #289056
build-mutter

00:01:21

 
  Test
passed #289057
test-mutter

00:02:27