Send problemNum to widgets' transform function

Summary:
It turns out we weren't actually sending problemNum to our widgets'
transform function, making radio randomization always the same!

See
https://www.khanacademy.org/private/content-improvement/high-school-content/e/geometric-descriptions
for some fun "just guess D" action

Test Plan:
Loaded [this item](http://localhost:9000/test.html#content=%7B%22question%22%3A%7B%22content%22%3A%22%2A%2AWhich%20is%20the%20most%20accurate%203D%20geometric%20description%20of%20the%20tower%20shown%20in%20the%20picture%20below%3F%2A%2A%5Cn%5Cn%2ANote%3A%20The%20tower%20has%20a%20square%20base.%2A%5Cn%5Cn%5B%5B%E2%98%83%20radio%201%5D%5D%5Cn%5Cn%24%5C%5Cqquad%24%21%5B%5D%28https%3A%2F%2Fka-perseus-images.s3.amazonaws.com%2Fd4e994a76f6d97d2ef3fa587a6a6edad179c2298.png%29%22%2C%22images%22%3A%7B%22https%3A%2F%2Fka-perseus-images.s3.amazonaws.com%2Fd4e994a76f6d97d2ef3fa587a6a6edad179c2298.png%22%3A%7B%22width%22%3A251%2C%22height%22%3A505%7D%7D%2C%22widgets%22%3A%7B%22radio%201%22%3A%7B%22type%22%3A%22radio%22%2C%22graded%22%3Atrue%2C%22options%22%3A%7B%22choices%22%3A%5B%7B%22content%22%3A%22The%20four%20sides%20of%20the%20tower%20rise%20up%20perpendicular%20to%20the%20ground.%20The%20topmost%20part%20of%20the%20roof%20can%20be%20modeled%20by%20a%20pyramid.%22%2C%22correct%22%3Atrue%7D%2C%7B%22content%22%3A%22On%20each%20of%20the%20two%20sides%20of%20the%20tower%20that%20we%20can%20see%2C%20there%20is%20a%20circle.%20Above%20the%20circles%20is%20the%20roof%2C%20which%20is%20shaped%20like%20a%20cone.%22%2C%22correct%22%3Afalse%7D%2C%7B%22content%22%3A%22The%20height%20of%20the%20tower%20is%20roughly%20equivalent%20to%20half%20the%20perimeter%20of%20its%20base.%22%2C%22correct%22%3Afalse%7D%2C%7B%22content%22%3A%22The%20tower%20is%20best%20modeled%20as%20a%20rectangle%20with%20a%20triangle%20on%20top.%22%7D%5D%2C%22randomize%22%3Atrue%2C%22multipleSelect%22%3Afalse%2C%22displayCount%22%3Anull%2C%22noneOfTheAbove%22%3Afalse%2C%22onePerLine%22%3Atrue%7D%2C%22version%22%3A%7B%22major%22%3A0%2C%22minor%22%3A0%7D%7D%7D%7D%2C%22answerArea%22%3A%7B%22type%22%3A%22multiple%22%2C%22options%22%3A%7B%22content%22%3A%22Select%20the%20correct%20answer.%22%2C%22images%22%3A%7B%7D%2C%22widgets%22%3A%7B%7D%7D%2C%22calculator%22%3Afalse%7D%2C%22itemDataVersion%22%3A%7B%22major%22%3A0%2C%22minor%22%3A1%7D%2C%22hints%22%3A%5B%7B%22content%22%3A%22Let%27s%20consider%20each%20answer%20choice%20in%20turn.%5Cn%5Cn%2A%20%2AThe%20tower%20is%20best%20modeled%20as%20a%20rectangle%20with%20a%20triangle%20on%20top.%2A%5Cn%5CnThis%20answer%20choice%20is%20incorrect%20because%20it%20is%20a%202D%20%28not%203D%29%20description%20of%20the%20tower.%22%2C%22images%22%3A%7B%7D%2C%22widgets%22%3A%7B%7D%7D%2C%7B%22content%22%3A%22%2A%20%2AThe%20height%20of%20the%20tower%20is%20roughly%20equivalent%20to%20half%20the%20perimeter%20of%20its%20base.%2A%5Cn%5CnThis%20answer%20choice%20is%20incorrect.%20We%20know%20that%20the%20base%20is%20a%20square.%20Half%20the%20perimeter%20of%20its%20base%20would%20be%20the%20combined%20length%20of%20two%20of%20the%20bottom%20edges%20of%20the%20tower.%20This%20length%20is%20much%20less%20than%20the%20height%20of%20the%20tower.%22%2C%22images%22%3A%7B%7D%2C%22widgets%22%3A%7B%7D%7D%2C%7B%22content%22%3A%22%2A%20%2AOn%20each%20of%20the%20two%20sides%20of%20the%20tower%20that%20we%20can%20see%2C%20there%20is%20a%20circle.%20Above%20the%20circles%20is%20the%20roof%2C%20which%20is%20shaped%20like%20a%20cone.%2A%5Cn%5CnThis%20answer%20is%20incorrect%20because%20the%20roof%20is%20shaped%20more%20like%20a%20pyramid%20than%20a%20cone.%20A%20cone%20has%20a%20circular%20base.%22%2C%22images%22%3A%7B%7D%2C%22widgets%22%3A%7B%7D%7D%2C%7B%22content%22%3A%22%2A%20%2AThe%20four%20sides%20of%20the%20tower%20rise%20up%20perpendicular%20to%20the%20ground.%20The%20topmost%20part%20of%20the%20roof%20can%20be%20modeled%20by%20a%20pyramid.%2A%5Cn%5CnThis%20is%20the%20correct%20answer.%20You%20should%20pick%20it.%22%2C%22images%22%3A%7B%7D%2C%22widgets%22%3A%7B%7D%7D%5D%7D)
over and over and made sure the correct choice ended up in four
different places.

Tried grading some of them

Auditors: charlie