fix bugs in searching file using keywords (infiniflow#780)

### What problem does this PR solve?


### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/db/services/file_service.py

@@ -34,9 +34,9 @@ def get_by_pf_id(cls, tenant_id, pf_id, page_number, items_per_page,
                      orderby, desc, keywords):
         if keywords:
             files = cls.model.select().where(
-                (cls.model.tenant_id == tenant_id)
+                (cls.model.tenant_id == tenant_id),
                 (cls.model.parent_id == pf_id),
-                (fn.LOWER(cls.model.name).like(f"%%{keywords.lower()}%%")),
+                (fn.LOWER(cls.model.name).contains(keywords.lower())),
                 ~(cls.model.id == pf_id)
             )
         else:

api/db/services/task_service.py

@@ -96,7 +96,7 @@ def do_cancel(cls, id):
             return doc.run == TaskStatus.CANCEL.value or doc.progress < 0
         except Exception as e:
             pass
-        return True
+        return False
 
     @classmethod
     @DB.connection_context()