Remove `prerecord_service_ping_data` feature flag

What does this MR do and why?

Related to #361332 (closed).

This removes prerecord_service_ping_data feature flag, it has been enabled by default since 15.0 and we don't need it anymore.

The removal also sets up groundwork for further refactoring of ServicePing::SubmitService for #361332 (closed).

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