Declare android.permission.READ_CONTACTS for Telecom.

Although not strictly required in the manifest due to the fact Telecom
runs as part of the system server, explicit definition of the permission
here provides ongoing documentation regarding which permissions are
used by the Telecom framework.

Test: Build, run telecom unit tests
Bug: 215661438
Change-Id: I35b27964ff7251563ed9ca640d26a50b14d4c783