UID2-7489: route /optout/status through the blocking handler when async batch requests are enabled

[sunnywu]

Summary

/v2/optout/status is a batch endpoint — it accepts up to optout_status_max_request_size (default 5000) advertising IDs per request and looks each up in the opt-out store. However, it was registered with a plain event-loop handler(...) regardless of the enable_async_batch_request flag, unlike the other batch/mapping endpoints:

Endpoint	enable_async_batch_request=true	=false
key/sharing, key/bidstream, identity/buckets, identity/map (v2/v3)	blockingHandler(..., false) (worker pool)	handler(...) (event loop)
optout/status (before)	handler(...) (event loop) — inconsistent	handler(...) (event loop)
optout/status (after)	blockingHandler(..., false) (worker pool)	handler(...) (event loop)

This PR moves the optout/status registration into the existing isAsyncBatchRequestsEnabled if/else (still guarded by optOutStatusApiEnabled), so it is offloaded to the Vert.x worker pool when async batch requests are enabled — mirroring identity/map.

Why

optout/status has the same "potentially heavy per-request work" profile as identity/map (up to 5000 lookups/request). When async batch offloading is enabled to keep the event loop responsive, this endpoint should be included; leaving it on the event loop undermines the purpose of the flag.

Risk / rollout

Low. With enable_async_batch_request=false (the current default) the behaviour is byte-for-byte identical to before — this is a no-op in current prod config. The worker-pool path only activates under the same flag that already governs the other batch endpoints, and the request/response contract is unchanged; only the executing thread differs. ordered=false matches the sibling endpoints (no cross-request ordering requirement).

Testing

• Added optOutStatusRequestWithAsyncBatchEnabled — asserts /v2/optout/status still returns a correct success response with enable_async_batch_request=true (i.e. via the blocking handler path).
• Ran the opt-out status + async-batch tests under JDK 21: 15 run, 0 failures, 0 errors.

Jira: UID2-7489

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