refactor: Removes the deprecated REMOVE_SLICE_LEVEL_LABEL_COLORS feature flag

RESOURCES/FEATURE_FLAGS.md

@@ -91,5 +91,4 @@ These features flags currently default to True and **will be removed in a future
 - ENABLE_TEMPLATE_REMOVE_FILTERS
 - GENERIC_CHART_AXES
 - KV_STORE
-- REMOVE_SLICE_LEVEL_LABEL_COLORS
 - VERSIONED_EXPORT

UPDATING.md

@@ -31,6 +31,7 @@ assists people when migrating to a new version.
 
 ### Breaking Changes
 
+- [26346](https://github.com/apache/superset/issues/26346): Removes the deprecated `REMOVE_SLICE_LEVEL_LABEL_COLORS` feature flag. The previous value of the feature flag was `False` and now the feature is permanently removed.
 - [26348](https://github.com/apache/superset/issues/26348): Removes the deprecated `CLIENT_CACHE` feature flag. The previous value of the feature flag was `False` and now the feature is permanently removed.
 - [26349](https://github.com/apache/superset/issues/26349): Removes the deprecated `DASHBOARD_CACHE` feature flag. The previous value of the feature flag was `False` and now the feature is permanently removed.
 - [26369](https://github.com/apache/superset/issues/26369): Removes the Filter Sets feature including the deprecated `DASHBOARD_NATIVE_FILTERS_SET` feature flag and all related API endpoints. The feature is permanently removed as it was not being actively maintained, it was not widely used, and it was full of bugs. We also considered that if we were to provide a similar feature, it would be better to re-implement it from scratch given the amount of technical debt that the current implementation has. The previous value of the feature flag was `False` and now the feature is permanently removed.

superset/config.py

@@ -431,7 +431,6 @@ class D3Format(TypedDict, total=False):
     "PRESTO_EXPAND_DATA": False,
     # Exposes API endpoint to compute thumbnails
     "THUMBNAILS": False,
-    "REMOVE_SLICE_LEVEL_LABEL_COLORS": False,  # deprecated
     "SHARE_QUERIES_VIA_KV_STORE": False,
     "TAGGING_SYSTEM": False,
     "SQLLAB_BACKEND_PERSISTENCE": True,

superset/dashboards/api.py

@@ -438,14 +438,6 @@ def get_charts(self, id_or_slug: str) -> Response:
         try:
             charts = DashboardDAO.get_charts_for_dashboard(id_or_slug)
             result = [self.chart_entity_response_schema.dump(chart) for chart in charts]
-
-            if is_feature_enabled("REMOVE_SLICE_LEVEL_LABEL_COLORS"):
-                # dashboard metadata has dashboard-level label_colors,
-                # so remove slice-level label_colors from its form_data
-                for chart in result:
-                    form_data = chart.get("form_data")
-                    form_data.pop("label_colors", None)
-
             return self.response(200, result=result)
         except DashboardAccessDeniedError:
             return self.response_403()