Improve handling of launching translucent occluding activities.

If the window is translucent we don't want to draw a solid color starting view. We also don't want to translate/scale it, since it's transparent.

Bug: 303010980
Test: launch assistant
Flag: com.android.systemui.translucent_occluding_activity_fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:22bbcfb1dabb95d2a1ec25bec59653c9946d27aa)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a61ffe42e31b1dd08ce0a9af73538fa048d0869d)
Merged-In: I11e75fe0215ab812d32ccc8aa2758b6fe58d86c3
Change-Id: I11e75fe0215ab812d32ccc8aa2758b6fe58d86c3