Do not force home status bar on dream

Currently when an ongoing call is active, the home status bar is forced
to be present to show the ongoing call state. However the dream overlay
renders its own status bar with ongoing call state. So this change
excludes dreaming with overlay case for the home status bar force-show.

Test: atest OngoingCallInteractorTest
Test: verified on device that the home status bar no longer shows on
      dream during a call
Bug: 422469252
Flag: com.android.systemui.ongoing_activity_chips_on_dream
Change-Id: Ie7808bbb229d3c969a48ff3b8038960b388bce27