[FIX] pos_loyalty: properly load loyalty_points for all partners

Before this commit, the loyalty_points field, neccessary to
implement the loyalty functionality in PoS in offline mode,
was only loaded properly for the partners at the start of
a PoS session.

After this commit, the loyalty_points are loaded properly for
every partner throughout the duration of the session, including
those that are loaded in the background or fetched when using
the search bar, which was not the case before.

Part-of: odoo/odoo#84719

addons/pos_loyalty/models/pos_session.py

@@ -58,6 +58,13 @@ class PosSession(models.Model):
 
     def _get_pos_ui_res_partner(self, params):
         result = super()._get_pos_ui_res_partner(params)
+        return self._load_pos_ui_loyalty_points(result)
+
+    def get_pos_ui_res_partner_by_params(self, custom_search_params):
+        partners = super().get_pos_ui_res_partner_by_params(custom_search_params)
+        return self._load_pos_ui_loyalty_points(partners)
+
+    def _load_pos_ui_loyalty_points(self, result):
         # In order to make loyalty programs work offline we load the partner's point into
         # a non-existant field 'loyalty_points'.
         if self.config_id.loyalty_program_id: