Resolve validations running on reject and therefore blocking it

[cammiida]

Description of the bug

When in a signing step, a user with write rights should have the possibility to "reject" the step. That is, go back (or wherever) to the relevant step configured in bpmn.
The user would typically reject in case of an error or if any of the signees didn't receive access to the form.
The validator triggered checks if all signees have signed, which will never happen in the case outlined above.

@ivarne might have some thoughts about this?

Steps To Reproduce

1. Go to the signing step in Signering Brukerstyrt.
2. Make sure you have write rights.
3. Try to click the reject button.
4. See that validation messages appear and that you haven't successfully rejected the step.

Additional Information

No response