Make sure salt.defaults.exitcodes is imported in saltcli tests
Make sure salt.defaults.exitcodes is imported in saltcli tests

https://github.com/saltstack/salt/pull/49217 added references to this
value in the module, but the module isn't imported. It happened to
already be imported elsewhere, but that was just a stroke of luck. This
makes the import explicit to avoid changes elsewhere in the codebase
causing these tests to suddenly start failing.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt