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/connector_app.py

@@ -26,7 +26,7 @@ from google_auth_oauthlib.flow import Flow
 
 from api.db import InputType
 from api.db.services.connector_service import ConnectorService, SyncLogsService
-from api.utils.api_utils import get_data_error_result, get_json_result, validate_request
+from api.utils.api_utils import get_data_error_result, get_json_result, get_request_json, validate_request
 from common.constants import RetCode, TaskStatus
 from common.data_source.config import GOOGLE_DRIVE_WEB_OAUTH_REDIRECT_URI, GMAIL_WEB_OAUTH_REDIRECT_URI, DocumentSource
 from common.data_source.google_util.constant import GOOGLE_WEB_OAUTH_POPUP_TEMPLATE, GOOGLE_SCOPES
@@ -38,7 +38,7 @@ from api.apps import login_required, current_user
 @manager.route("/set", methods=["POST"])  # noqa: F821
 @login_required
 async def set_connector():
-    req = await request.json
+    req = await get_request_json()
     if req.get("id"):
         conn = {fld: req[fld] for fld in ["prune_freq", "refresh_freq", "config", "timeout_secs"] if fld in req}
         ConnectorService.update_by_id(req["id"], conn)
@@ -90,7 +90,7 @@ def list_logs(connector_id):
 @manager.route("/<connector_id>/resume", methods=["PUT"])  # noqa: F821
 @login_required
 async def resume(connector_id):
-    req = await request.json
+    req = await get_request_json()
     if req.get("resume"):
         ConnectorService.resume(connector_id, TaskStatus.SCHEDULE)
     else:
@@ -102,7 +102,7 @@ async def resume(connector_id):
 @login_required
 @validate_request("kb_id")
 async def rebuild(connector_id):
-    req = await request.json
+    req = await get_request_json()
     err = ConnectorService.rebuild(req["kb_id"], connector_id, current_user.id)
     if err:
         return get_json_result(data=False, message=err, code=RetCode.SERVER_ERROR)
@@ -211,7 +211,7 @@ async def start_google_web_oauth():
             message="Google OAuth redirect URI is not configured on the server.",
         )
 
-    req = await request.json or {}
+    req = await get_request_json()
     raw_credentials = req.get("credentials", "")
 
     try: