Remap "SIP_NOT_FOUND" to INVALID_NUMBER.

Remapping CODE_SIP_NOT_FOUND error code to INVALID_NUMBER instead of
SERVER_UNREACHABLE.  Apparently SIP_NOT_FOUND is more analogous to
invalid number.

Bug: 111909355
Test: Added unit test
Merged-In: Ibe008c63b5d946013da19b8b9e7d4c9c312d050f
Change-Id: I4e927a565420fa215859fd2eee5b035a30db699f

# Conflicts:
#	tests/telephonytests/src/com/android/internal/telephony/imsphone/ImsPhoneCallTrackerTest.java