feat(product-analytics): roll out validation for test account filters for mcp/api

[thmsobrmlr]

Problem

We added validations for test account filters, but couldn't roll them out due to invalid entries in production.

Changes

These have now been fixed, let's roll the validations out.

How did you test this code?

n/a

[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat(product-analytics): roll out valida..." | Re-trigger Greptile}

[github-actions]

Simple rollout of existing guarded validation — removes a feature flag so previously opt-in strict validation of test account filters is now always enforced. The validation logic itself is unchanged; tests are updated correctly to match. No data model, dependency, or security concerns.

[github-actions]

🎭 Playwright didn't run on this PR — your changes touch code that could affect E2E behavior, but Playwright is opt-in via label now to keep CI cost down.

Add the run-playwright label if you want an E2E sweep before merging — CI will pick it up automatically.

Most PRs don't need this. Real regressions still get caught on master and fix-forward.

[greptile-apps]

_{Reviews (2): Last reviewed commit: "Merge branch 'master' into roll-out-test..." | Re-trigger Greptile}

[deployment-status-posthog]

Deploy status

Environment	Status	Deployed At	Workflow
dev	✅ Deployed	2026-05-18 11:46 UTC	Run
prod-us	✅ Deployed	2026-05-18 11:57 UTC	Run
prod-eu	✅ Deployed	2026-05-18 12:14 UTC	Run