Telemetry#obtainTelemetry should be public

[tobrun]

Telemetry#obtainTelemetry is package private while it should be public. End developers need to be able to roll their own custom attribution. As part of that, they need to allow end users to opt-in or out of telemetry collection. To do this they need a reference to Telemetry which is not possible atm.

[tobrun]

In #12024 I opted to limit the scope solely to address the issue from OP by exposing 2 configurations instead of exposing the whole object. cc @zugaldia