feat(core): Add multi-main setup debug endpoint (no-changelog) (#7991)

## Summary
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Adi's idea here to help diagnose:
https://n8nio.slack.com/archives/C069KJBJ8HE/p1702300349277609?thread_ts=1702299930.728029&cid=C069KJBJ8HE
...

#### How to test the change:
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## Issues fixed
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## Review / Merge checklist
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- [ ] Tests included.
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  >
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packages/cli/src/Server.ts

@@ -120,6 +120,7 @@ import { CollaborationService } from './collaboration/collaboration.service';
 import { RoleController } from './controllers/role.controller';
 import { BadRequestError } from './errors/response-errors/bad-request.error';
 import { NotFoundError } from './errors/response-errors/not-found.error';
+import { MultiMainSetup } from './services/orchestration/main/MultiMainSetup.ee';
 import { PasswordUtility } from './services/password.utility';
 
 const exec = promisify(callbackExec);
@@ -307,6 +308,11 @@ export class Server extends AbstractServer {
 			Container.get(RoleController),
 		];
 
+		if (Container.get(MultiMainSetup).isEnabled) {
+			const { DebugController } = await import('./controllers/debug.controller');
+			controllers.push(Container.get(DebugController));
+		}
+
 		if (isLdapEnabled()) {
 			const { service, sync } = LdapManager.getInstance();
 			controllers.push(new LdapController(service, sync, internalHooks));