Improve export server data validation / sync with client side data model

[ZhangYiJiang]

Report: https://sentry.io/nusmods/export/issues/434914645/

Error: Evaluation failed: TypeError: Cannot use 'in' operator to search for 'CFG1010' in undefined
    at <anonymous>:1:47499
    at Array.forEach (<anonymous>)
    at m (<anonymous>:1:47477)
    at t.value (<anonymous>:1:177575)
    at l (<anonymous>:1:217005)
    at beginWork (<anonymous>:1:221406)
    at o (<anonymous>:1:209902)
    at a (<anonymous>:1:210223)
    at u (<anonymous>:1:210461)
    at _ (<anonymous>:1:213995)
  File "<anonymous>", line 1, in null.<anonymous>
  ?, in Array.forEach
  File "<anonymous>", line 1, in m
  File "<anonymous>", line 1, in t.value
  File "<anonymous>", line 1, in l
...
(8 additional frame(s) were not displayed)

Error: Evaluation failed: TypeError: Cannot use 'in' operator to search for 'CFG1010' in undefined
    at <anonymous>:1:47499
    at Array.forEach (<anonymous>)
    at m (<anonymous>:1:47477)
    at t.value (<anonymous>:1:177575)
    at l (<anonymous>:1:217005)
    at beginWork (<anonymous>:1:221406)
    at o (<anonymous>:1:209902)
    at a (<anonymous>:1:210223)
    at u (<anonymous>:1:210461)
    at _ (<anonymous>:1:213995)

There's something in here that's causing the export server to crash. I can reproduce reliably in production, but not locally, which is really annoying

[ZhangYiJiang]

Ah, I know what's wrong. The data is missing the colors key - this export URL was created by an old version of the client. The validator should probably be updated so that this gets flagged up as a validation error instead of crashing the server, but it's not critical.