[FIX] partner_autocomplete: correctly manage empty country data

Steps to reproduce:
1) Enter a vat number in a customer field (for exemple Sales Order)
2) Click on the suggestion
=> Traceback

Task-ID 2059940

closes odoo/odoo#37180

Signed-off-by: Rémi Rahir (rar) <rar@odoo.com>

addons/mail/models/mail_thread.py

@@ -2080,6 +2080,9 @@ class MailThread(models.AbstractModel):
             create_values['partner_ids'] = [(4, pid) for pid in create_values.get('partner_ids', [])]
             create_values['channel_ids'] = [(4, cid) for cid in create_values.get('channel_ids', [])]
             create_values_list.append(create_values)
+        if 'default_child_ids' in self._context:
+            ctx = {key: val for key, val in self._context.items() if key != 'default_child_ids'}
+            self = self.with_context(ctx)
         return self.env['mail.message'].create(create_values_list)
 
     # ------------------------------------------------------

addons/partner_autocomplete/models/res_partner.py

@@ -50,8 +50,8 @@ class ResPartner(models.Model):
         if not country:
             country = self.env['res.country'].search([['name', '=ilike', country_name]])
 
-        state_id = {}
-        country_id = {}
+        state_id = False
+        country_id = False
         if country:
             country_id = {
                 'id': country.id,