OO-4392: update group name after selecting an other group in GTA

src/main/java/org/olat/course/nodes/gta/ui/GTAParticipantController.java

@@ -840,6 +840,7 @@ public class GTAParticipantController extends GTAAbstractController implements A
 				cleanUpProcess();
 				resetDueDates();
 				assessedGroup = businessGroupChooserCtrl.getSelectGroup();
+				setGroupHeaders(assessedGroup);
 				process(ureq);
 			}
 			chooserCalloutCtrl.deactivate();