Fix voicemail notification for Sprint.

Sprint voicemail notification wasn't showing up because we were
looking for a CSIM application on the UICC and couldn't find it.
Added code to CDMAPhone.onUpdateIccAvailability() to load the USIM
application if we fail to get the CSIM application.

Bug: 9908333
Change-Id: I5c69c9eea6972e377b10a4057492f9ecc8233028