Feat: Alter flask to Quart for async API serving. (#11275)

### What problem does this PR solve?

#11277

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/apps/file2document_app.py

@@ -19,8 +19,8 @@ from pathlib import Path
 from api.db.services.file2document_service import File2DocumentService
 from api.db.services.file_service import FileService
 
-from flask import request
-from flask_login import login_required, current_user
+from quart import request
+from api.apps import login_required, current_user
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.utils.api_utils import server_error_response, get_data_error_result, validate_request
 from common.misc_utils import get_uuid
@@ -33,8 +33,8 @@ from api.utils.api_utils import get_json_result
 @manager.route('/convert', methods=['POST'])  # noqa: F821
 @login_required
 @validate_request("file_ids", "kb_ids")
-def convert():
-    req = request.json
+async def convert():
+    req = await request.json
     kb_ids = req["kb_ids"]
     file_ids = req["file_ids"]
     file2documents = []
@@ -103,8 +103,8 @@ def convert():
 @manager.route('/rm', methods=['POST'])  # noqa: F821
 @login_required
 @validate_request("file_ids")
-def rm():
-    req = request.json
+async def rm():
+    req = await request.json
     file_ids = req["file_ids"]
     if not file_ids:
         return get_json_result(