Set an UPS account number to the custom agent in test scenario

#14876
(grafted from a7803b7036e7dad73a932d0483a03f51e734a95d)

--HG--
branch : 8.0

modules/stock_package_shipping_ups/tests/scenario_stock_package_shipping_ups_international.rst

@@ -72,6 +72,7 @@ Create parties::
     >>> agent_identifier.code = "CHE-123.456.788 IVA"
     >>> agent_party.save()
     >>> agent = Agent(party=agent_party)
+    >>> agent.ups_account_number = os.getenv('UPS_ACCOUNT_NUMBER')
     >>> agent.save()
     >>> AgentSelection(to_country=switzerland, agent=agent).save()