Session is not getting expired even after closing the browser in Developer portal

Bug description

When the user is closing the browser without signing out from the developer portal, the user session is not getting expired.
The session is active once we load the developer portal again and users need not to login again.

Reproduction steps

1. Login into Developer Portal
2. Close the browser without signing out
3. Open the browser again and load developer portal URL
4. Navigate to the Profile page and check User details who logged in earlier

Expected behavior

Once we close the browser user session should be expired and it should ask for login once again we open the browser and load the developer portal URL.

Is your portal managed or self-hosted?

Managed

Environment

- Operating system: Windows
- Browser: Google Chrome, Firefox

Additional context

The same scenario is working as expected in the legacy developer portal.
i.e. Once we close the browser without signing out, the session is expiring and asking for sign in if we open and load the developer portal url.