Fix issues when opening glanceable hub slowly

When opening the glanceable hub with a slow drag, it seems that
SceneContainerLayout may not consume all touches. Instead of returning
the result of dispatchTouchEvent, we just return true from our touch
handling logic as the touch should not be seen by anyone else.

Bug: 315207481
Test: atest NotificationShadeWindowViewControllerTest GlanceableHubContainerControllerTest
Flag: ACONFIG com.android.systemui.communal_hub DEVELOPMENT
Change-Id: I7d5964e0ed7d62c9ff71d9bdf51452080cc81ced