DO NOT MERGE HFP: Fix out of bound access in phone number processing

* Write at most sizeof(dialnum) chars into dialnum array in ClccResponse
  method
* Write at most sizeof(ag_res.str) - 5 chars into ag_res.str array in
  PhoneStateChange method

Bug: 79431031
Bug: 79266386
Test: make call with super long phone numbers
Change-Id: I98e7687ac4055800aa46626c6b1c866e52e474df
Merged-In: I98e7687ac4055800aa46626c6b1c866e52e474df