Refa: make RAGFlow more asynchronous (#11601)

### What problem does this PR solve?

Try to make this more asynchronous. Verified in chat and agent
scenarios, reducing blocking behavior. #11551, #11579.

However, the impact of these changes still requires further
investigation to ensure everything works as expected.

### Type of change

- [x] Refactoring

api/apps/__init__.py

@@ -13,13 +13,12 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 #
+import logging
 import os
 import sys
-import logging
 from importlib.util import module_from_spec, spec_from_file_location
 from pathlib import Path
 from quart import Blueprint, Quart, request, g, current_app, session
-from werkzeug.wrappers.request import Request
 from flasgger import Swagger
 from itsdangerous.url_safe import URLSafeTimedSerializer as Serializer
 from quart_cors import cors
@@ -40,7 +39,6 @@ settings.init_settings()
 
 __all__ = ["app"]
 
-Request.json = property(lambda self: self.get_json(force=True, silent=True))
 
 app = Quart(__name__)
 app = cors(app, allow_origin="*")