[FIX] point_of_sale: display correct uom on weighable products

Everything's displayed fine on orderlines with weighable products, this
only affected the small blue labels on the products.

opw-674264

addons/point_of_sale/static/src/xml/pos.xml

@@ -751,7 +751,7 @@
                 </t>
                 <t t-if="product.to_weight">
                     <span class="price-tag">
-                        <t t-esc="widget.format_currency(product.price,'Product Price')+'/Kg'"/>
+                        <t t-esc="widget.format_currency(product.price,'Product Price')+'/'+widget.pos.units_by_id[product.uom_id[0]].name"/>
                     </span>
                 </t>
             </div>