requireAuth does not properly handle invalidated token

### [REQUIRED] Environment info

**firebase-tools:** all

**Platform:** all

### [REQUIRED] Test case

Googler's need to run `firebase login --reauth` every day. However `requireAuth` only checks if `configstore` has a `user` entry, not if the tokens are still valid.

The result is when you run `firebase init emulators` or any other auth command you get:
```
Error: Failed to list Firebase projects. See firebase-debug.log for more info.
```

It would be good if `getAccessToken()` or other auth base functions could detect invalid auth.

### [REQUIRED] Steps to reproduce

See above

### [REQUIRED] Expected behavior

See above

### [REQUIRED] Actual behavior

See above