[Ongoing Call] Catch a security exception instead of crashing SysUI.

This will mean that the ongoing call chip will stay visible even when
the user is in the calling process. However, this is much better than
crashing SysUI.

Fixes: 216693695
Bug: 216489355
Bug: 216248574
Test: verified starting a call won't crash SysUI even with ag/16659008
in the build.
Test: new unit test

Change-Id: I1108fc6fe01f284364331dd9de57ebe9390d4d78
Merged-In: I1108fc6fe01f284364331dd9de57ebe9390d4d78