Fix hub touch handling breaking after using gestures on hub over dream

The DreamOverlayService has its own TouchMonitor that needs to be shut
off once the glanceable hub shows up. If the dream starts underneath
the hub, such as if you dock while the hub is open, or if we restart
the dream under the hub, this is not done correctly.

This causes touch handlers for both the hub and the dream to run when
performing gestures over the hub, which leads to touch sessions getting
stuck and stop all subsequent gestures from working.

This changes the logic in DreamOverlayService to not always set its
lifecycle state to RESUMED once dreaming starts, which turns on touch
monitoring, but instead sets it conditionally based on whether or not
anything is covering the dream.

Bug: 337094073
Fix: 337094073
Test: atest DreamOverlayServiceTest
      also verified manually that touch handling works on and off dream
Flag: ACONFIG com.android.systemui.communal_hub TEAMFOOD
Change-Id: I59b941889b67e5daf491be2ae2c77934698d7d19