FeatureFlags: Revert managing feature flags outside of settings.Cfg (#44382)

* Revert "FeatureToggles: register all enterprise feature toggles (#44336)"

This reverts commit f53b3fb007.

* Revert "FeatureFlags: manage feature flags outside of settings.Cfg (#43692)"

This reverts commit f94c0decbd.

pkg/tsdb/testdatasource/stream_handler.go

@@ -37,7 +37,7 @@ func (s *Service) SubscribeStream(_ context.Context, req *backend.SubscribeStrea
 		}
 	}
 
-	if s.features.IsLivePipelineEnabled() {
+	if s.cfg.FeatureToggles["live-pipeline"] {
 		// While developing Live pipeline avoid sending initial data.
 		initialData = nil
 	}
@@ -126,7 +126,7 @@ func (s *Service) runTestStream(ctx context.Context, path string, conf testStrea
 			}
 
 			mode := data.IncludeDataOnly
-			if s.features.IsLivePipelineEnabled() {
+			if s.cfg.FeatureToggles["live-pipeline"] {
 				mode = data.IncludeAll
 			}