Merge OpenOLAT 12.1 to OpenOLAT default branch with 9cefeabbaab8b3bfa9f94f0bfce0411d0de1dbd3

src/main/java/org/olat/course/assessment/bulk/ValidationStepForm.java

@@ -164,7 +164,7 @@ public class ValidationStepForm extends StepFormBasicController {
 
 			for(String prop : userPropsToSearch) {
 				List<Identity> found = userManager.findIdentitiesWithProperty(prop, assessedId);
-				if(found.size() > 0) {
+				if(found != null && found.size() > 0) {
 					// ignore multiple hits, just take the first one
 					identity = found.get(0);
 					idToIdentityMap.put(assessedId, identity);