do not accept 425 as `file should not exist`

[individual-it]

@Then as :user :entry :path should not exist will accept any 4xx return code as valid see https://github.com/opencloud-eu/opencloud/blob/fb8af22073cee757a1aeed54cd30aa2fda9615eb/tests/acceptance/bootstrap/WebDav.php#L1267 I think 425 should not be accepted, but in that case it should retry