Fix improper SIM Missing automatic navigation

* Properly allow the user to go backwards to prior to the SIM Missing
  page, if it had ever appeared and then a SIM became available.
* Ignore the activity result. Wizard remains on SIM Missing page until
  user chooses to leave or returns to wizard with SIM present.

Change-Id: I3edac6cbb03d76c66b04673d6104e98189ce365c