Verify plugin examples from slot `README`s are valid

I tried using the example code from https://github.com/openedx/frontend-app-learner-dashboard/tree/frontend-base/src/slots/CourseBannerSlot by updating site.config.dev.tsx to be

-import { EnvironmentTypes, SiteConfig, footerApp, headerApp, shellApp } from '@openedx/frontend-base';
+import { EnvironmentTypes, WidgetOperationTypes, SiteConfig, footerApp, headerApp, shellApp } from '@openedx/frontend-base';
 
 import { learnerDashboardApp } from './src';
 
+import { Alert } from '@openedx/paragon';
+
 import '@openedx/frontend-base/shell/style';
 
+const myComponent = ({ cardId }) => (
+  <Alert variant="info" className="mb-0">
+    Course banner for course with {cardId}
+  </Alert>
+)
+
 const siteConfig: SiteConfig = {
   siteId: 'learner-dashboard-dev',
   siteName: 'Learner Dashboard Dev',
@@ -17,7 +25,17 @@ const siteConfig: SiteConfig = {
     shellApp,
     headerApp,
     footerApp,
-    learnerDashboardApp
+    {
+      ...learnerDashboardApp,
+      slots: [
+        {
+          slotId: 'org.openedx.frontend.slot.learnerDashboard.courseCardBanner.v1',
+          id: 'my.widget',
+          op: WidgetOperationTypes.REPLACE,
+          component: myComponent
+        },
+      ]
+    },
   ],
   externalRoutes: [
     {

and got

adding relatedId: 'defaultContent', fixes the error. I'm not sure if that is supposed to be required for using WidgetOperationTypes.REPLACE or not

Compare the CourseBannerSlot README example with the shown site.config.dev.tsx setup, focusing on WidgetOperationTypes.REPLACE and the relatedId value. Reproduce the reported error, determine whether relatedId is required, and verify that the README example and its expected result are valid.