Delete Corresponding Minio Bucket When Deleting a Knowledge Base (#7841)

### What problem does this PR solve?

Delete Corresponding Minio Bucket When Deleting a Knowledge Base
[issue #4113 ](https://github.com/infiniflow/ragflow/issues/4113)

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)

rag/utils/minio_conn.py

@@ -118,3 +118,13 @@ class RAGFlowMinio:
                 time.sleep(1)
         return
 
+    def remove_bucket(self, bucket):
+        try:
+            if self.conn.bucket_exists(bucket):
+                objects_to_delete = self.conn.list_objects(bucket, recursive=True)
+                for obj in objects_to_delete:
+                    self.conn.remove_object(bucket, obj.object_name)
+                self.conn.remove_bucket(bucket)
+        except Exception:
+            logging.exception(f"Fail to remove bucket {bucket}")
+