Make PATCH to change aup signature time working for client credentials

AUDIT logs are now:

// Client credentials flow (note that client-cred is the client id)
2024-07-05 16:28:18.395  INFO 16774 --- [nio-8080-exec-7] AUDIT                                    : {"@type":"AupSignedOnBehalfEvent","timestamp":1720189698394,"category":"AUP","principal":"client: client-cred","message":"Client client-cred signed the AUP on behalf of test user","signature":{"aupId":1,"username":"test","signatureTime":"2024-07-05T16:28:18.387+02:00"},"source":"AupSignatureController"}

// Other flows linked to user identity
2024-07-05 16:29:42.316  INFO 16774 --- [nio-8080-exec-9] AUDIT                                    : {"@type":"AupSignedOnBehalfEvent","timestamp":1720189782316,"category":"AUP","principal":"user: 73f16d93-2441-4a50-88ff-85360d78c6b5","message":"User 73f16d93-2441-4a50-88ff-85360d78c6b5 signed the AUP on behalf of test user","signature":{"aupId":1,"username":"test","signatureTime":"2024-07-05T16:29:42.315+02:00"},"source":"AupSignatureController"}

indigo-iam / iam

Make PATCH to change aup signature time working for client credentials #804

Quality Gate passed