Filter self managed phone accounts out when finding emergency accts.

Filter out self managed phone accounts from the list of potential accts
when placing an emergency call.  We will NEVER place a call over a self
managed phone account in an emergency situation.

Test: Added new CTS test to verify that we don't try to place call over
the self-managed acct.
Bug: 208680522

Change-Id: I4be2bff670ce047916c48be541abe59c7d51331c