frontend-app-api: removed deprecated FrontendFeature type

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/frontend-test-utils/src/app/renderInTestApp.tsx

@@ -16,10 +16,7 @@
 
 import { Fragment } from 'react';
 import { Link, MemoryRouter } from 'react-router-dom';
-import {
-  createSpecializedApp,
-  FrontendFeature,
-} from '@backstage/frontend-app-api';
+import { createSpecializedApp } from '@backstage/frontend-app-api';
 import { RenderResult, render } from '@testing-library/react';
 import { ConfigReader } from '@backstage/config';
 import { JsonObject } from '@backstage/types';
@@ -33,6 +30,7 @@ import {
   RouterBlueprint,
   NavItemBlueprint,
   createFrontendPlugin,
+  FrontendFeature,
 } from '@backstage/frontend-plugin-api';
 import appPlugin from '@backstage/plugin-app';