Fix that pending DTMF cannot be sent after SRVCC has occurred

The pause dial information is not moved to GsmCdmaConnection
from ImsPhoneConnection when the SRVCC has occurred.
Therefore, it is not possible to send the pending DTMF
after the SRVCC has occurred.

Test: manual
Bug: 35367717

Change-Id: I28f68767a3c5ca2ba65e8eff7e124021bcb0f3cd