Ensure error messages are displaying when a Job Application doesn't save

[epintozzi]

We currently have a handful of actions on our BE that will send errors to the FE for Job Application. Please ensure these errors messages will display and that we are testing them as such for the FE:

• 400 on create
• 400 on show
• 404 on show
• 400 on update
• 404 on update
• 404 on destroy

[epintozzi]

Blocked by #124