[FIX] point_of_sale: Slow customer search

Steps to reproduce the bug:
- Have a lot of res_partners (more than 100,000)
- Search for a customer

Bug:
The app freezes while searching

opw:2302765

closes odoo/odoo#58469

X-original-commit: 7c7269fa6152795ffaf6a0c8e9c2261d7ca8aaae
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>
Signed-off-by: backspac <backspac@users.noreply.github.com>

addons/point_of_sale/static/src/js/db.js

@@ -290,6 +290,8 @@ var PosDB = core.Class.extend({
                                   (partner.country_id ? partner.country_id[1]: '');
                 this.partner_search_string += this._partner_search_string(partner);
             }
+
+            this.partner_search_string = utils.unaccent(this.partner_search_string);
         }
         return updated_count;
     },
@@ -320,7 +322,7 @@ var PosDB = core.Class.extend({
         }
         var results = [];
         for(var i = 0; i < this.limit; i++){
-            var r = re.exec(utils.unaccent(this.partner_search_string));
+            var r = re.exec(this.partner_search_string);
             if(r){
                 var id = Number(r[1]);
                 results.push(this.get_partner_by_id(id));