style: enable import-x/no-duplicates (#6279)

packages/backend/server/tests/mailer.spec.ts

@@ -1,5 +1,6 @@
 import type { INestApplication } from '@nestjs/common';
-import ava, { type TestFn } from 'ava';
+import type { TestFn } from 'ava';
+import ava from 'ava';
 import Sinon from 'sinon';
 
 import { AppModule } from '../src/app.module';