Fix API error in catalog graph plugin

Signed-off-by: James Brooks <jamesbrooks@spotify.com>

.changeset/cool-baboons-count.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-graph': patch
+---
+
+Add missing API implementation for catalog graph plugin in NFS apps.

plugins/catalog-graph/src/alpha.tsx

@@ -15,6 +15,7 @@
  */
 
 import {
+  ApiBlueprint,
   createFrontendPlugin,
   PageBlueprint,
 } from '@backstage/frontend-plugin-api';
@@ -24,7 +25,11 @@ import {
 } from '@backstage/core-compat-api';
 import { EntityCardBlueprint } from '@backstage/plugin-catalog-react/alpha';
 import { catalogGraphRouteRef, catalogEntityRouteRef } from './routes';
-import { Direction } from '@backstage/plugin-catalog-graph';
+import {
+  catalogGraphApiRef,
+  DefaultCatalogGraphApi,
+  Direction,
+} from '@backstage/plugin-catalog-graph';
 
 const CatalogGraphEntityCard = EntityCardBlueprint.makeWithOverrides({
   name: 'relations',
@@ -85,6 +90,15 @@ const CatalogGraphPage = PageBlueprint.makeWithOverrides({
   },
 });
 
+const CatalogGraphApi = ApiBlueprint.make({
+  params: defineParams =>
+    defineParams({
+      api: catalogGraphApiRef,
+      deps: {},
+      factory: () => new DefaultCatalogGraphApi(),
+    }),
+});
+
 export default createFrontendPlugin({
   pluginId: 'catalog-graph',
   info: { packageJson: () => import('../package.json') },
@@ -94,7 +108,7 @@ export default createFrontendPlugin({
   externalRoutes: {
     catalogEntity: convertLegacyRouteRef(catalogEntityRouteRef),
   },
-  extensions: [CatalogGraphPage, CatalogGraphEntityCard],
+  extensions: [CatalogGraphPage, CatalogGraphEntityCard, CatalogGraphApi],
 });
 
 export { catalogGraphTranslationRef } from './translation';