Update docuemntation on some Telecom-specific resources.

1. `config_requireCallCapableAccountForHandle` should never have existed
and is effectively a bug to have it set to `false`, so it is not used
any more.
2. `unloggable_phone_numbers` moves into the Telecom framework so that
OEMs can customize this in the future Telecom module.

Flag: com.android.server.telecom.flags.resolve_hidden_dependencies_two
Bug: 308205987
Test: Re-run unit tests and perform basic correctness testing.
Change-Id: I74fd039d8a86c6eda78c22e164bbfa3b5355b341