[flexiglass] Fix remote input case when notifs aren't overflowing

The LaunchedEffect to return the scrim to 0 offset when stack height isn't overflowing was fighting the LaunchedEffect that changes scrim offset to make room for the IME.

Bug: 375632579
Test: manually verified scrim offset correctly changes for inline reply in this scenario
Flag: com.android.systemui.scene_container
Change-Id: Id494c49f91408c3e68c9b967072e6eb7fea025a4