chore(rollback): Expose feature flag to API (#80431)

Initially created here, but was not being exposed:
https://github.com/getsentry/sentry/pull/80031

We will need this to check this on the Sentry app frontend in order to
display the entry point UI.

src/sentry/features/temporary.py

@@ -360,7 +360,7 @@ def register_temporary_features(manager: FeatureManager):
     # Enable version 2 of reprocessing (completely distinct from v1)
     manager.add("organizations:reprocessing-v2", OrganizationFeature, FeatureHandlerStrategy.INTERNAL, api_expose=False)
     # Enable Sentry's 2024 Rollback feature
-    manager.add("organizations:sentry-rollback-2024", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=False)
+    manager.add("organizations:sentry-rollback-2024", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable resolve in upcoming release
     # TODO(steve): Remove when we remove the feature from the UI
     manager.add("organizations:resolve-in-upcoming-release", OrganizationFeature, FeatureHandlerStrategy.OPTIONS, api_expose=True)