feat(user-settings): Search for user avatar also in the entities

If the identity system doesn't provide an avatar, but the existing
user entity does have the correct annotation use that as the profile
avatar.

Fixes #26838

Signed-off-by: Łukasz Jernaś <lukasz.jernas@allegro.com>

plugins/user-settings/dev/index.tsx

@@ -17,10 +17,37 @@
 import React from 'react';
 import { CatalogEntityPage } from '@backstage/plugin-catalog';
 import { createDevApp } from '@backstage/dev-utils';
-import { userSettingsPlugin, UserSettingsPage } from '../src/plugin';
+import { UserSettingsPage, userSettingsPlugin } from '../src';
+import { CatalogApi, catalogApiRef } from '@backstage/plugin-catalog-react';
+import {
+  CompoundEntityRef,
+  Entity,
+  UserEntity,
+} from '@backstage/catalog-model';
 
+const userEntity: UserEntity = {
+  apiVersion: 'backstage.io/v1beta1',
+  kind: 'User',
+  metadata: {
+    name: 'Guest',
+  },
+  spec: {},
+};
 createDevApp()
   .registerPlugin(userSettingsPlugin)
+  .registerApi({
+    api: catalogApiRef,
+    deps: {},
+    factory() {
+      return {
+        async getEntityByRef(
+          _: string | CompoundEntityRef,
+        ): Promise<Entity | undefined> {
+          return userEntity;
+        },
+      } as Partial<CatalogApi> as unknown as CatalogApi;
+    },
+  })
   .addPage({
     title: 'Settings',
     path: '/settings',