fix: populate items during initialization

charts/waterfallchart/src/styling-panel-property-definiton.js

@@ -5,16 +5,17 @@
  * @returns definition or undefined if nothing is toggled on by feature flags
  */
 const getStylingItems = (flags, styleOptions) => {
-  const items = {};
-  items.axisLabelSection = {
-    translation: 'properties.axis.label',
-    component: 'panel-section',
-    items: styleOptions.getOptions('axis', 'axis.label.name'),
-  };
-  items.valueLabelSection = {
-    translation: 'properties.value.label',
-    component: 'panel-section',
-    items: styleOptions.getOptions('value', 'label.value'),
+  const items = {
+    axisLabelSection: {
+      translation: 'properties.axis.label',
+      component: 'panel-section',
+      items: styleOptions.getOptions('axis', 'axis.label.name'),
+    },
+    valueLabelSection: {
+      translation: 'properties.value.label',
+      component: 'panel-section',
+      items: styleOptions.getOptions('value', 'label.value'),
+    },
   };
 
   if (flags?.isEnabled('CLIENT_IM_3051')) {