Move settings initialization after module init phase (#3438)

### What problem does this PR solve?

1. Module init won't connect database any more.
2. Config in settings need to be used with settings.CONFIG_NAME

### Type of change

- [x] Refactoring

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

api/apps/dialog_app.py

@@ -20,7 +20,7 @@ from api.db.services.dialog_service import DialogService
 from api.db import StatusEnum
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.user_service import TenantService, UserTenantService
-from api.settings import RetCode
+from api import settings
 from api.utils.api_utils import server_error_response, get_data_error_result, validate_request
 from api.utils import get_uuid
 from api.utils.api_utils import get_json_result
@@ -175,7 +175,7 @@ def rm():
             else:
                 return get_json_result(
                     data=False, message='Only owner of dialog authorized for this operation.',
-                    code=RetCode.OPERATING_ERROR)
+                    code=settings.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)