[FIX] point_of_sale: float comparison

- Create the following pricelist for product A:
  4 Units: 2.88
  3 Units: 3.45
  2 Units: 4.85
  1 Units: 7.50
- In the POS, click several time on A to add in the cart

The 2 first units are merged in a single line, but from the third one a
new line is created.

This is because of the float reproesentation of 4.85, which becomes
4.8500000000000005.

opw-1887586

closes odoo/odoo#27539

addons/point_of_sale/static/src/js/models.js

@@ -1508,6 +1508,7 @@ exports.Orderline = Backbone.Model.extend({
     // when we add an new orderline we want to merge it with the last line to see reduce the number of items
     // in the orderline. This returns true if it makes sense to merge the two
     can_be_merged_with: function(orderline){
+        var price = parseFloat(round_di(this.price || 0, this.pos.dp['Product Price']).toFixed(this.pos.dp['Product Price']));
         if( this.get_product().id !== orderline.get_product().id){    //only orderline of the same product can be merged
             return false;
         }else if(!this.get_unit() || !this.get_unit().is_pos_groupable){
@@ -1516,7 +1517,7 @@ exports.Orderline = Backbone.Model.extend({
             return false;
         }else if(this.get_discount() > 0){             // we don't merge discounted orderlines
             return false;
-        }else if(this.price !== orderline.get_product().get_price(orderline.order.pricelist, this.get_quantity())){
+        }else if(price !== orderline.get_product().get_price(orderline.order.pricelist, this.get_quantity())){
             return false;
         }else if(this.product.tracking == 'lot') {
             return false;