Removed Notification Delays when adding / removing notifications

This leads to nicer transitions with physics rather than wobbling.

Outstanding (regardless of the physics flag or this change):
Fix overlapping notifications with row transparency.

Bug: 393581344
Test: manual
Flag: com.android.systemui.physical_notification_movement
Change-Id: I455f3b10fa091776275391e4cef9a5a1de309115