[FIX] point_of_sale: new session should open with user as cashier

Open a new session with user A, the cashier is A.
Close the session and post the entries.
The responsible for the session is user A and the salesman on the sale order is A.

Then log in to the database with user B.
Open a new session on the same pos.

Before this commit, the cashier on the second session was A

After this commit, the cashier on the second session is B

OPW 1864207
closes #25628

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

@@ -221,7 +221,7 @@ exports.PosModel = Backbone.Model.extend({
         fields: ['id', 'journal_ids','name','user_id','config_id','start_at','stop_at','sequence_number','login_number'],
         domain: function(self){ return [['state','=','opened'],['user_id','=',session.uid]]; },
         loaded: function(self,pos_sessions){
-            self.pos_session = pos_sessions[0]; 
+            self.pos_session = pos_sessions[0];
         },
     },{
         model: 'pos.config',
@@ -241,6 +241,8 @@ exports.PosModel = Backbone.Model.extend({
 
             self.db.set_uuid(self.config.uuid);
             self.cashier = self.get_cashier();
+            // We need to do it here, since only then the local storage has the correct uuid
+            self.db.save('pos_session_id', self.pos_session.id);
 
             var orders = self.db.get_orders();
             for (var i = 0; i < orders.length; i++) {
@@ -577,6 +579,10 @@ exports.PosModel = Backbone.Model.extend({
 
     // returns the user who is currently the cashier for this point of sale
     get_cashier: function(){
+        // reset the cashier to the current user if session is new
+        if (this.db.load('pos_session_id') !== this.pos_session.id) {
+            this.set_cashier(this.user);
+        }
         return this.db.get_cashier() || this.cashier || this.user;
     },
     // changes the current cashier