fix(forms): Cannot save record with file=required field

[dtroelofsprins]

What version of EMX2 are you using (see footer)
v11.23.1

Describe the bug
Saving a record where a field of type=file which is required is included is not possible:

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://emx2.dev.molgenis.org'
2. Create a new schema using PET_STORE template
3. Go to schema, User table and put picture column required=True
4. Save schema and go to tables => User
5. Enter a new row and file in data, include a file
6. Save the record => see the error
7. When file is not required, record can be saved without any problem.

Expected behavior
A column with type=file should also be included as a required field. OR it should be made clear in the manual that this is not possible.