[IMP] snailmail: create notifications in batch

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Task ID-2330149
COM PR odoo/odoo#61246
ENT PR odoo/enterprise#14561

addons/snailmail/models/snailmail_letter.py

@@ -97,8 +97,9 @@ class SnailmailLetter(models.Model):
             })
         letters = super().create(vals_list)
 
+        notification_vals = []
         for letter in letters:
-            self.env['mail.notification'].sudo().create({
+            notification_vals.append({
                 'mail_message_id': letter.message_id.id,
                 'res_partner_id': letter.partner_id.id,
                 'notification_type': 'snail',
@@ -107,6 +108,8 @@ class SnailmailLetter(models.Model):
                 'notification_status': 'ready',
             })
 
+        self.env['mail.notification'].sudo().create(notification_vals)
+
         return letters
 
     def _fetch_attachment(self):