Fix unable to resume show-when-lock activity

When the show-when-lock activity is becoming top because the
other top non-show-when-lock activities are removed or moved
to back, the occluded state may not been updated that causes
activity state stays at stopped and visible.

Bug: 115499058
Test: atest CtsActivityManagerDeviceTestCases:KeyguardTests
Change-Id: I540f591755b51da777480f8b3ae2a8bedfc2ff5f