Fix bug for auth on page refresh

[godwinpang]

Config token needs to be set on auth changed (in auth listener) otherwise when we refresh the page we won't have the token.

https://github.com/HKN-UCSD/hkn-member-portal/blob/5a21c9c33dd1da7c9d1069b5ba61d17c1f9c71c3/src/pages/App/index.js#L46

[thai-truong]

Btw for this one, probably shouldn't set config token in setClaims() and only set token in onAuthStateChanged(). onAuthStateChanged() runs first, so if userToken state is not set before the set config token call in setClaims(), then userToken is null, meaning the set config token call in setClaims() will set token to empty string, which stops users from signing in when they click on the sign in button for the first time. After that, they sign in normally.

This is just what I encountered doing some testing with querying for roles using backend api : )