refac: async webhook request

backend/open_webui/routers/auths.py

@@ -625,7 +625,7 @@ async def signup(request: Request, response: Response, form_data: SignupForm):
             )
 
             if request.app.state.config.WEBHOOK_URL:
-                post_webhook(
+                await post_webhook(
                     request.app.state.WEBUI_NAME,
                     request.app.state.config.WEBHOOK_URL,
                     WEBHOOK_MESSAGES.USER_SIGNUP(user.name),

backend/open_webui/routers/channels.py

@@ -209,7 +209,7 @@ async def send_notification(name, webui_url, channel, message, active_user_ids):
                 )
 
                 if webhook_url:
-                    post_webhook(
+                    await post_webhook(
                         name,
                         webhook_url,
                         f"#{channel.name} - {webui_url}/channels/{channel.id}\n\n{message.content}",