Rework isAbleToDream signal

Still seeing bugs where the device comes out of AOD, goes
to LOCKSCREEN, but then back to DREAMING because SysUI
is not told fast enough that the dream ended. Add a very
large delay when leaving dozing before processing any
dreaming information. This should be OK as AOD->DREAMING
isn't really supported anyways

Test: atest KeyguardInteractorTest
Fixes: 356356505
Flag: com.android.systemui.migrate_clocks_to_blueprint
Change-Id: I6733a2dad73389d096bb3032e42b45155a0a15a2