Fix lock screen overlap test.

This change fixes the rectangle reported for accessibility of the shelf when on the lockscreen, which ensures that overlap tests operate correctly.

Fixes: 235118701
Test: atest LockscreenNotificationsOverlapWithLockIcon
Test: manual testing with talkback on using ltr and rtl
Change-Id: I71eb7f54244a620f0431ae519ae1c7405d8d412d