PanelQueryRunner: Return previous processed (transform+field config) series for loading state (#67768)

* Return same series for loading state

* Fix shared query issue

* include structureRev

* heatmap should depend on the series, not the wrapper

* fix more panels

* keep config for comparison

* fieldConfig.fieldConfig!

* cleanup

* cmon

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Co-authored-by: Leon Sorokin <leeoniya@gmail.com>
Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

public/app/plugins/panel/histogram/HistogramPanel.tsx

@@ -13,7 +13,7 @@ export const HistogramPanel = ({ data, options, width, height }: Props) => {
   const theme = useTheme2();
 
   const histogram = useMemo(() => {
-    if (!data?.series?.length) {
+    if (!data.series.length) {
       return undefined;
     }