fix(task groups): correct the validation of new group field
fix(task groups): correct the validation of new group field

Related to: CAM-3023

TitanUser/camunda-bpm-webapp,TitanUser/camunda-bpm-webapp,incedure/incedure-datalist-ui,tcrossland/camunda-bpm-webapp,nagyistoce/camunda-tasklist-ui,kingtec/camunda-tasklist-ui,xlinur/camunda-bpm-webapp,tcrossland/camunda-bpm-webapp,xlinur/camunda-bpm-webapp,nagyistoce/camunda-tasklist-ui,TitanUser/camunda-bpm-webapp,xlinur/camunda-bpm-webapp,kingtec/camunda-tasklist-ui,tcrossland/camunda-bpm-webapp