[Settings] Prevent crash from abnormal behavior for ApnSettings page.

 - The problem is user remove SIM when stop in ApnSettings page, and do
 unexpected operation.

 - To figure out this problem, listen SIM absent event and make activity
 finish at this moment.

Bug: 189909956
Test: Manual test.
Merged-In: I179c708debcbc31ba9a93e4e434ae810051f5004
Change-Id: If59f68f595794695600811224cdedb4692b869c0