[Asset graph] Fix query error notice (#27273)

## Summary & Motivation
This is due to the full asset graph data not being available. Not really
sure why the fetchResult.loading is false when the data is not available
yet... but for now fixing it this way until I can investigate deeper.

js_modules/dagster-ui/packages/ui-core/src/asset-graph/useAssetGraphData.tsx

@@ -94,7 +94,7 @@ export function useFullAssetGraphData(options: AssetGraphFetchScope) {
       });
   }, [options.loading, queryItems]);
 
-  return {fullAssetGraphData, loading: fetchResult.loading || options.loading};
+  return {fullAssetGraphData, loading: !fetchResult.data || fetchResult.loading || options.loading};
 }
 
 export type GraphDataState = {