Allow injecting DreamTouchHandlers into DreamOverlayComponent.

This changelist enables DreamTouchHandlers to be specified when
creating a new DreamOverlayComponent through its Factory. The
DreamOverlayService will specify no additional handlers until the
complication layer has been separated from the dream overlay.

Test: atest DreamOverlayServiceTest
Bug: 261781069
Change-Id: I041d45059e443c61ce5eb497319999858e544508