Allow the creation of short answer free response questions

[rtibbles]

Desired behavior

When an assessment resource has been set to Survey via the work in #4875 - it should be possible to create a question of type "short answer free response".

This question type would only require the prompt part of the question, and would not need any sort of answer field, so when created it would simply require the input of the question field and nothing else.

While this will be implicitly feature flagged by it being blocked for non-Survey assessments, we should explicitly hide it based on the same feature flag as described in #4875

Current behavior

Currently it is only possible to create multiple choice and numeric input questions in the Studio frontend.