Issue 127875492: USSD progress dialog didn't dismiss when user press cancel button.

[root cause ]When user click cancel button of USSD dialog, ImsPhone will terminate this session, but UI didn't get this state.
[changes ] ImsPhoneMmiCode should receive EVENT_USSD_CANCEL_COMPLETE and notify UI dismiss dialog.
[Issue address] https://partnerissuetracker.corp.google.com/u/0/issues/127875492

Change-Id: I6c3ca4a63d4f8874352676f51c16f99f5dc5a534