Disallow dreaming when auto projected display is active

Dreams cannot start in this state anyways. Attempting to dream simply
does nothing in this state, which is unexpected when pressing the power
button to start dream.

Bug: 413508543
Fixes: 413508543
Test: atest DreamManagerServiceTest
      manually verified on device
Flag: android.service.dreams.disallow_dream_on_auto_projection
Change-Id: I0b4da17ad23f89173bd28b190b9ab57e6d76a07b