🔧 chore(slack charts): removed unused handlers (#87820)

i removed the usage of this flags in some earlier slack refactor pr, but
forgot to remove it from manager

Author: iamrajjoshi

src/sentry/features/temporary.py

@@ -350,9 +350,6 @@ def register_temporary_features(manager: FeatureManager):
     manager.add("organizations:insights-session-health-tab-ui", OrganizationFeature, FeatureHandlerStrategy.FLAGPOLE, api_expose=True)
     # Lets organizations manage grouping configs
     manager.add("organizations:set-grouping-config", OrganizationFeature, FeatureHandlerStrategy.INTERNAL, api_expose=True)
-    # Add regression chart as image to slack message
-    manager.add("organizations:slack-endpoint-regression-image", OrganizationFeature, FeatureHandlerStrategy.OPTIONS, api_expose=False)
-    manager.add("organizations:slack-function-regression-image", OrganizationFeature, FeatureHandlerStrategy.OPTIONS, api_expose=False)
     # Enable SAML2 Single-logout
     manager.add("organizations:sso-saml2-slo", OrganizationFeature, FeatureHandlerStrategy.OPTIONS, api_expose=False)
     # Show links and upsells to Insights modules