Update RetCode to common.constants (#10984)

### What problem does this PR solve?

1. Update RetCode to common.constants
2. Decouple the admin and API modules

### Type of change

- [x] Refactoring

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

api/apps/dialog_app.py

@@ -22,9 +22,9 @@ from api.db import StatusEnum
 from api.db.services.tenant_llm_service import TenantLLMService
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.user_service import TenantService, UserTenantService
-from api import settings
 from api.utils.api_utils import server_error_response, get_data_error_result, validate_request
 from common.misc_utils import get_uuid
+from common.contants import RetCode
 from api.utils.api_utils import get_json_result
 
 
@@ -219,7 +219,7 @@ def rm():
             else:
                 return get_json_result(
                     data=False, message='Only owner of dialog authorized for this operation.',
-                    code=settings.RetCode.OPERATING_ERROR)
+                    code=RetCode.OPERATING_ERROR)
             dialog_list.append({"id": id,"status":StatusEnum.INVALID.value})
         DialogService.update_many_by_id(dialog_list)
         return get_json_result(data=True)