Quiz doesn't start

[AdrianOrlow]

Some users are having a problem with the quiz page. Sometimes it locks out (user can't get out of the loading state) or server doesn't respond to requests (although the backend process seems to work correctly).

Second of these is strictly related to the API, so I created a separate issue about it mypolitics/mypolitics-api#3.

The first issue is a little more complex. It can be fixed with the use of a browser privacy mode or clearing site data, so it's certainly caused by the wrong method of redux state persisting. At this point, I don't know why it doesn't work correctly for some users.

The issues were reported previously in #2 #5 #4.