[mdns] fix the logic of finding the existing service

When adding a service, the MdnsRecordRepository finds the
existing service solely by service name, which is wrong. it should check
both the service name and the service type.

Bug: 325862182

Change-Id: I72c6837d0dfb41fc9b2d7763e18b3f5415f8c0d9
2 files changed