Add "not supported" string for MMI codes not supported by network.

Bug: 230841132
Test: Added new unit tests to verify the correct message is generated
when the network reports that a feature is not supported.

Change-Id: Idc7dc648dbe001d39d2e5a02803df38d98589aaf
Merged-In: Idc7dc648dbe001d39d2e5a02803df38d98589aaf