Allow floating IME to apply final state.

Floating IME has zero insets and hence it becomes a special case where
Insets type to side map will have to be statically created per
form-factor. Realistically, IME side shouldn't change on any
form-factor.

Fix: 142713934
Test: Manually
     1. Enable floating mode in gboard.
     2. Tap on editor to verify gboard shows
     3. press back to verify gboard hides.

Change-Id: Ie2e2df3fdc5f637cf2efdf14bb5b74f45e3a929f