Don't place the modal clickable for invisible overlays

This CL moves the isInvisible behavior for Content in
SceneTransitionLayoutImpl so that the modal clickable is also not placed
when the associated overlay is invisible.

Bug: 433909610
Test: atest SceneTransitionLayoutTest
Flag: com.android.systemui.scene_container
Change-Id: If04811deb09ba5c8d13740586e49beec7195789a