Fixed an issue where opaque huns would clip the following notifs

Previously HUNs appearing on top of other huns would clip them
mostly away. Now they are excluded if they are opaque since
overlaps don't have to be ensured there.

Fixes: 422658515
Test: atest SystemUITests
Flag: com.android.systemui.physical_notification_movement
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:3ee40b051f1a4b60bbe785e971c827e8757cbafb)
Merged-In: Idf4f2d90fd57d0245fdd7e6d7a15a2adc08050a4
Change-Id: Idf4f2d90fd57d0245fdd7e6d7a15a2adc08050a4