Fix view of empty fields in OPR

[vismayajochem]

Description of the issue

Empty fields are not shown or marked as empty when doing the OPR. One has to click on one to get the information

Steps to Reproduce

1. Do an OPR
2. Click on an empty field

Ideas of solution

Fields which don't have an entry, empty fields, are not clickable, grey and have the message "Field is empty. Reviewing is not possible." written there immediately.

Context and Environment

• Version used:
• Operating system:
• Environment setup and (python) version:

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