Also translate separator when moving shelf icons

Shelf separator should also be translated otherwise it won't be
horizontally aligned to the clock separator.

Test: visual
Test: atest packages/SystemUI/tests/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayoutTest.java
Change-Id: I0df8aee288466a680f78b5d70cc42138e54b3540
Fixes: 72527703