Not possible to clear an ID once set

[fatso83]

Describe the bug
Create a new form and assign an id to it, then clear the field and try to click anywhere. You know get an error about the new blank value not passing the regex.

Id må være fra 1-64 tegn og kan kun inneholde bokstaver fra a-z, tall, - og .

To Reproduce
Steps to reproduce the behavior:

1. Create new form on https://formdesigner.helsenorgelab.no/
2. Click the (i) to get to Skjemadetaljer
3. Click the "Id" field, enter a value and exit the field
4. Clear the Id field
5. Observe an error text

Expected behavior
Since an ID is optional, one should not validate blank strings.

Screenshots