Study on the Long-term Use of Etanercept in Children and Adolescents with 3 Subtypes of Juvenile Idiopathic Arthritis. An Open-Label Extension Study to Assess the Long-Term Safety and Clinical Benefit of Etanercept in Children and Adolescents With Extended Oligoarticular Juvenile Idiopathic Arthritis, Enthesitis Related Arthritis, or Psoriatic Arthritis Who Were Previously Enrolled in Protocol 0881A1-3338-WW (B1801014)