Patching null dereference in AbstractFloatingView.getOpenView()

If there is a better solution, bug assignee, please proceed with it.

I'll land this immediately, as a lot of tests are broken.

Bug: 130739123
Change-Id: Iacdb9adbbf41f1f9de1390c3e7525ee0bd7beda6
(cherry picked from commit 5a22ef7e)