Restore user picture in add user dialog on rotation

Picture was being cached in OnSaveInstanceState method in background thread. It finished saving after the restoration was happening in OnRestoreInstanceState and therefore the picture could not be retrieved. Picture is now saved straight after choosing and retrieved when dialog gets created.

Bug: 293435121
Test: atest CreateUserDialogControllerTest
Change-Id: Ic3aa22d19732c5480075cea613070e0de19ad73e