Enable save before saving to update form after save (#15579)

diff --git a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.js b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.js
index a58516c..53184b2 100644
--- a/erpnext/healthcare/doctype/patient_appointment/patient_appointment.js
+++ b/erpnext/healthcare/doctype/patient_appointment/patient_appointment.js
@@ -111,6 +111,7 @@
 					frm.set_value('appointment_time', selected_slot);
 					frm.set_value('duration', data.time_per_appointment);
 					d.hide();
+					frm.enable_save();
 					frm.save();
 				}
 			});