s_packaging_calculator: contained mapping depends on lang

Otherwise translations won't be taken into account.

stock_packaging_calculator/models/product.py

@@ -24,6 +24,7 @@ class Product(models.Model):
         help="Technical field to store contained packaging. ",
     )
 
+    @api.depends_context("lang")
     @api.depends("packaging_ids.qty")
     def _compute_packaging_contained_mapping(self):
         for rec in self: