Fixes#6999
It appears that at some point one of the operations causes focus to move
away for non-native fullscreen. We previously relied on the delegate
method to restore this but a better approach appears to handle this
directly in the fullscreen implementations. This fixes the linked issue.
I still think long term all the `Ghostty.moveFocus` stuff is a code
smell and we should be auditing all that code to see if we can
eliminate it. But this is a step in the right direction, and removes one
of those uses.