use constant for message handler

src/modules/ad/interface/message-handlers/ad-created.message-handler.ts

@@ -3,13 +3,14 @@ import { RabbitSubscribe } from '@mobicoop/message-broker-module';
 import { CommandBus } from '@nestjs/cqrs';
 import { CreateAdCommand } from '@modules/ad/core/application/commands/create-ad/create-ad.command';
 import { Ad } from './ad.types';
+import { AD_CREATED_MESSAGE_HANDLER } from '@src/app.constants';
 
 @Injectable()
 export class AdCreatedMessageHandler {
   constructor(private readonly commandBus: CommandBus) {}
 
   @RabbitSubscribe({
-    name: 'adCreated',
+    name: AD_CREATED_MESSAGE_HANDLER,
   })
   public async adCreated(message: string) {
     try {