[FIX] point_of_sale: print amount of guests correctly on ESC/POS receipt

Before this the only thing that would ever be printed was 'Guests: ',
because it was only added when receipt.customer_count evaluated to
false. Another issue is that receipt.customer_count doesn't exist in the
point_of_sale module. It is created by pos_restaurant, so there's where
it should be added to the receipt.

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

@@ -679,9 +679,6 @@
                         <div>Served by <t t-esc='receipt.cashier' /></div>
                     </div>
                 </t>
-                <t t-if='!receipt.customer_count'>
-                    <div>Guests: <t t-esc='receipt.customer_count' /></div>
-                </t>
             </div>
             <br /><br />
 

addons/pos_restaurant/static/src/xml/floors.xml

@@ -6,6 +6,9 @@
             <t t-if='receipt.table'>
                 at table <t t-esc='receipt.table' />
             </t>
+            <t t-if='receipt.customer_count'>
+                <div>Guests: <t t-esc='receipt.customer_count' /></div>
+            </t>
         </t>
     </t>