FF-2509 CI job to validate test data

[greghuels]

This runs a new yarn validate:tests script to validate test data. With assignmentDetails now existing, it will be easy to make a change to assignment and forget to update the values in assignmentDetails, so this job prevents against that situation.

[felipecsl]

nice work! only feedback would be around using jest for a more standard setup here that's easier to expand, but not blocking on this

[greghuels]

nice work! only feedback would be around using jest for a more standard setup here that's easier to expand, but not blocking on this

Thanks for the feedback! I'll update with Jest -- I think you're right.

[greghuels]

@felipecsl