Fail to load web page in DevContainer

[zhangjiale-64]

Describe the issue: When both the Flask development server and the web application are started, open the url http://localhost:3000/, the following error message appears: Repro Steps:

1. Run azd auth login.
2. Run azd up.
3. Run cd backend .
4. Run python3 -m venv venv and source venv/bin/activate.
5. Run poetry install.
6. Run azd env get-values > .env.
7. Run poetry run generate.
8. Run cd ../frontend and npm install.
9. Run cd ../backend and python main.py.
10. Open a new terminal.
11. Run cd frontend and npm run dev.
12. Open the url http://localhost:3000/.

Environment:

• Azd version: azd version 1.9.5 (commit cd2b7af9995d358aab33c782614f801ac1997dde)
• OS: Dev Containers

Expected behavior: The web pag can load normally.

@jongio and @marlenezw for notification.

[faynef]

@marlenezw Based on the latest code test, this issue can still be reproduced.

CC: @jongio