Add casing to disable form on preview revisions

dashboard/src/main/home/cluster-dashboard/expanded-chart/ExpandedChart.tsx

@@ -855,6 +855,7 @@ const ExpandedChart: React.FC<Props> = (props) => {
                     }}
                     renderTabContents={renderTabContents}
                     isReadOnly={
+                      isPreview ||
                       imageIsPlaceholder ||
                       !isAuthorized("application", "", ["get", "update"])
                     }