refactor: remove all unused imports (#9951)

Co-authored-by: tamaina <tamaina@hotmail.co.jp>

packages/backend/src/daemons/QueueStatsService.ts

@@ -1,6 +1,5 @@
-import { Inject, Injectable } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import Xev from 'xev';
-import { DI } from '@/di-symbols.js';
 import { QueueService } from '@/core/QueueService.js';
 import { bindThis } from '@/decorators.js';
 import type { OnApplicationShutdown } from '@nestjs/common';