Enable showing forwarded number

This commit adds some changes to:
-control the forwarded number display as per carrier config.
-store forwarded number into extras.

Test: manual - Confirmed that it stores forwarded number in
EXTRA_LAST_FORWARDED_NUMBER.
Test: auto - Passed FrameworksTelephonyTests
Bug: 29063067

Change-Id: Ib85d88073037b7b2f87717bb2dda174004499a3e
1 file changed