Check doze transition before attempting to getState()

getState throws and IllegalStateException if there
are pending transitions, so we need to gate
checks for DozeMachine.getState() to ensure
there are no transitions being executed.

If the device is in the middle of a doze transition,
then don't update the dock state.

Fixes: 320622153
Flag: NONE
Test: atest DozeDockHandlerTest
Test: manually send a lot of delayed notifications and then
dock device

Change-Id: I0aa2da1b7d507d77bb5978f0dd0340bca20b4d8d