Fix login to work with server side switch to simple token

[pratimasakinala]

Describe the bug

Logging in, and staying logged in, do not work once you have the changes from PR 369 on the server-side.

Expected behavior

The client should:

• allow users to log in
• not request sign-in again on refresh, or after closing the tab or browser.

To Reproduce

1. After activating the seed user, try to log in.
2. The page refreshes but you stay at the login page. No error is shown but if you look at the Developer Console, you'll see a 401 error when the app tries to go to the Agents page.