[REF] purchase_receipt_expectation: fix create() side effects

The create() modifies the vals dict assing the 'name' key to it.
This caused the several creastes to always use the same PO number,
and that can be a problem for other purchase modules.

purchase_receipt_expectation/tests/test_purchase_receipt_expectation.py

@@ -44,7 +44,7 @@ def test_00_automatic_receipt(self):
             - `receipt_expectation` must be "automatic" (as default value)
             - At least one picking should have been created
         """
-        order = self.env["purchase.order"].create(self.po_vals)
+        order = self.env["purchase.order"].create(self.po_vals.copy())
         self.assertEqual(order.receipt_expectation, "automatic")
         order.button_confirm()
         self.assertTrue(order.picking_ids)
@@ -91,14 +91,14 @@ def _create_picking_for_succeeding_receipt_expectation(self):
         self.registry.setup_models(self.cr)
 
         succeeding_order = self.env["purchase.order"].create(
-            dict(self.po_vals, receipt_expectation="succeeding")
+            dict(self.po_vals.copy(), receipt_expectation="succeeding")
         )
         self.assertEqual(succeeding_order.receipt_expectation, "succeeding")
         succeeding_order.button_confirm()
         self.assertTrue(succeeding_order.picking_ids)
 
         failing_order = self.env["purchase.order"].create(
-            dict(self.po_vals, receipt_expectation="failing")
+            dict(self.po_vals.copy(), receipt_expectation="failing")
         )
         with self.assertRaises(NotImplementedError) as error:
             failing_order.button_confirm()