Draft: Add 1-way communication with Secret Detection Service

What does this MR do and why?

Issue #473440

This MR switches the monolith to use the SDS-produced gem for secret detection instead of the built-in one.

Following on that, we want to add 1-way communication to the SDS so we can start to gather metrics for the eventual production rollout of the SDS without risking production's performance and current behavior.

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