add kind on write condition

Author: emjay0921

spp_farmer_registry_base/models/farm.py

@@ -111,7 +111,7 @@ def update_group_head_member(self, new_group_head):
     def write(self, vals):
         farm = super().write(vals)
         for rec in self:
-            if rec.is_group:
+            if rec.is_group and rec.kind == self.env.ref("spp_farmer_registry_base.kind_farm").id:
                 head_member = rec.get_group_head_member()
                 if not head_member:
                     raise ValidationError(_("Farm must have a head member."))