Re-throw error in custom map form so that it appears on frontend (#16580)

frontend/src/metabase/admin/settings/components/widgets/CustomGeoJSONWidget.jsx

@@ -62,6 +62,7 @@ export default class CustomGeoJSONWidget extends Component {
       await this.props.reloadSettings();
     } catch (e) {
       console.warn("Save failed: ", e);
+      throw e;
     }
   };
 
@@ -338,7 +339,7 @@ const EditMap = ({
           </SettingContainer>
         </div>
       </div>
-      <div className="flex-full ml4 relative bordered rounded flex my4">
+      <div className="flex-auto ml4 relative bordered rounded flex my4">
         {geoJson || geoJsonLoading || geoJsonError ? (
           <LoadingAndErrorWrapper loading={geoJsonLoading} error={geoJsonError}>
             {() => (