chore: Remove vercel logs feature flag from backend (#103975)

The Vercel Log Drain is now GA
(getsentry/sentry-options-automator#5786,
https://docs.sentry.io/product/drains/integration/vercel/#log-drains).

We need to start cleaning up the feature flags. This PR removes the flag
from the backend.

resolves
https://linear.app/getsentry/issue/LOGS-395/clean-up-feature-flags-for-vercel-log-drains

We've done this on the frontend
(#103940) and relay
(getsentry/relay#5406), and [relay has
deployed](https://deploy.getsentry.net/go/compare/deploy-relay-pop/532/with/533),
so this is a safe change.

Author: AbhiPrasad

src/sentry/features/temporary.py

@@ -329,8 +329,6 @@ def register_temporary_features(manager: FeatureManager) -> None:
     manager.add("organizations:relay-otlp-traces-endpoint", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enables OTLP Log ingestion in Relay for an entire org.
     manager.add("organizations:relay-otel-logs-endpoint", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
-    # Enables Vercel Log Drain ingestion in Relay for an entire org.
-    manager.add("organizations:relay-vercel-log-drain-endpoint", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enables Prevent AI in the Sentry UI
     manager.add("organizations:prevent-ai", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enables Prevent AI Configuration Page in the Sentry UI

src/sentry/relay/config/__init__.py

@@ -73,7 +73,6 @@
     "organizations:indexed-spans-extraction",
     "organizations:relay-otlp-traces-endpoint",
     "organizations:relay-otel-logs-endpoint",
-    "organizations:relay-vercel-log-drain-endpoint",
     "organizations:ourlogs-ingestion",
     "organizations:tracemetrics-ingestion",
     "organizations:view-hierarchy-scrubbing",