Fix a few issues with ime adjust/minimized dock stack

- Do not override minimized state in SysUI when IME adjust change
comes in.
- Do not animate IME adjust if we are already animating for minimized.
This lead to problems that we animated the minimized state with the IME
adjust values.
- Make sure to update state after checking whether the IME adjust is
animating. This is to fix an issue where sometimes the IME adjust
animation didn't run because the old target was wrong.

Change-Id: Ie35e2f943a4cda99ffdc6f14663d892863759e46
Fixes: 28819201