Correct the dialing number of structured MMI.

According to TS 22.030 6.5.2 "Structure of the MMI", the dialing number
can not end with #. The format is like *SC*SI#DN. Correct the mmi pattern
to exclude DN# case. With this fix, processCode() will tread *NNN#DN#,
e.g. *400#16 digit number# in bug 5622718, as USSD and send via
RIL_REQUEST_SEND_USSD.

bug:5622718
Change-Id: Ifc8d0edff4308602a5f3fc651cf116bf6bad3cbc