Refactor:improve the logic to check cancel (#8524)

### What problem does this PR solve?

improve the logic to check cancel

### Type of change

- [x] Refactoring

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Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

rag/svr/task_executor.py

 import numpy as np
 from peewee import DoesNotExist
 
-from api.db import LLMType, ParserType, TaskStatus
+from api.db import LLMType, ParserType
 from api.db.services.document_service import DocumentService
 from api.db.services.llm_service import LLMBundle
 from api.db.services.task_service import TaskService
     canceled = False
     task = TaskService.get_task(msg["id"])
     if task:
-        _, doc = DocumentService.get_by_id(task["doc_id"])
-        canceled = doc.run == TaskStatus.CANCEL.value or doc.progress < 0
+        canceled = TaskService.do_cancel(task["id"])
     if not task or canceled:
         state = "is unknown" if not task else "has been cancelled"
         FAILED_TASKS += 1