flags(dashboards): add flag for async queue (#103235)

Add feature flag for async queue of dashboard widget queries

Author: DominikB2014

src/sentry/features/temporary.py

@@ -514,6 +514,8 @@ def register_temporary_features(manager: FeatureManager) -> None:
     manager.add("organizations:visibility-explore-equations", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable equations feature in dashboards
     manager.add("organizations:visibility-dashboards-equations", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
+    # Enable an async queue for dashboard widget queries
+    manager.add("organizations:visibility-dashboards-async-queue", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable the new explore page
     manager.add("organizations:visibility-explore-view", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Enable high date range options on new explore page