Loan policy: Data silently fails to save when interval is missing

Steps to repro:

1. Log into folio-testing
2. Go to Settings > Circulation > Loan policies
3. Create a loan policy
4. Specify the "Grace period", "Recall return interval", "Minimum guaranteed loan period for recalled items", "Alternate loan period at checkout for items with an active, pending hold request" and or "Alternate loan period at renewal for items with an active, pending hold request" without selecting an interval for the time
5. Save
6. View the saved record
7. The data you entered was not saved

Expected:

• Form should not save and silently discard entered data. Instead, save should be prevented. The interval menus should be highlighted and a red validation message should read, "Please select to continue"
• If a unit has been selected but no quantity has been specified, please display "Please fill this in to continue"

Actual: Data silently discareded

Screencast: https://www.screencast.com/t/En8cPh2M