message: Fix error when mapper activity was using a flow output field and the field was removed.
diff: @@ -1498,7 +1498,8 @@ export class FlowComponent implements OnInit, OnDestroy {
  private cleanDanglingTaskOutputMappings(outputRegistry: Map<string, boolean>) {
  const isMapperContribAndHasMapping = (task: Task) => {
  const schema = this.flowState.schemas[task.ref];
  - return !!(isMapperActivity(schema) && task.attributes.inputs.length);
  + const inputs = (task.attributes || {}).inputs || [];
  + return isMapperActivity(schema) && inputs.length > 0;
  };
  _.filter(this._getAllTasks(), isMapperContribAndHasMapping)
  .forEach((task: Task) => {
  