[RONs-AOD] clean AOD Skeleton parent before using it

Notifications inflate AOD Skeleton View on the background thread. When AndroidView needs re-composition, existing AOD Skeleton view can't be used since it has a parent. This CL removes it's parent to re-use it.

Fixes: 425120767
Flag: com.android.systemui.ui_rich_ongoing_aod_skeleton_bg_inflation
Test: Have a RON and wait for device to transition to LockScreen. No crash is expected.
Change-Id: I30a9d53d353f2f929cca1f23678a833050fd45ee