Missing validation check in volunteerTable.js

For some reason, a user was able to submit a application to the off-site moderation team without any questions, so the `volunteer.questions` field is set to `undefined`.
This causes the whole table for the role to not show.

Suggested solution:
Add additional validation and error handling here to catch error like this from breaking the UI.
Try to figure out how the situation happened in the first place.

Start by reading volunteerTable.js and trace how the table uses volunteer.questions when it is undefined. Investigate how an off-site moderation application can be submitted without questions, then add validation and error handling so that malformed data does not prevent the role's table from rendering. Done means this case no longer breaks the UI and its cause is understood.

Written by the indexing model from the issue text.