fix(dashboard): chart fullscreen issue when filter pane is collapsed (#28428)

superset-frontend/src/dashboard/components/gridComponents/ChartHolder.tsx

@@ -96,7 +96,7 @@ const ChartHolder = ({
   const theme = useTheme();
   const fullSizeStyle = css`
     && {
-      position: fixed;
+      position: fixed !important;
       z-index: 3000;
       left: 0;
       top: 0;