Error: Invalid state: password page with no partialToken

[sentry-io]

Sentry Issue: XPRO-1KX

Error: Invalid state: password page with no partialToken
  at None (./static/js/containers/pages/login/LoginPasswordPage.js:60:13)
  at tc (None:43:11)
  at a (None:37:1)
  at None (None:37:1)
  at initializePromise ([native code])
...
(8 additional frame(s) were not displayed)

[rhysyngsun]

Seems to be an issue where the following sequence happens:

• User tries to login, enteres password
• Login attempt fails because the response they're getting has no partialToken
• User clicks button a second time, which triggers this error because of the assertion

I'd thought we were covering all cases for no partialToken, but there must be at least one more to deal with.

[pdpinch]

That particular Sentry error is gone, but there seem to be plenty of others: https://sentry.io/organizations/mit-office-of-digital-learning/issues/?project=1413655&query=is%3Aunresolved+password+page+with+no+partialToken&statsPeriod=14d