backend-app-api: Remove deprecated service implementations

Co-authored-by: Camila Belo <camilaibs@gmail.com>
Signed-off-by: Johan Haals <johan.haals@gmail.com>

plugins/proxy-backend/src/service/router.credentials.test.ts

@@ -14,10 +14,8 @@
  * limitations under the License.
  */
 
-import {
-  authServiceFactory,
-  httpAuthServiceFactory,
-} from '@backstage/backend-app-api';
+import { authServiceFactory } from '@backstage/backend-defaults/auth';
+import { httpAuthServiceFactory } from '@backstage/backend-defaults/httpAuth';
 import {
   mockServices,
   registerMswTestHooks,