Code review comment for lp:~mskalka/juju-ci-tools/assess-destroy-model

I modified the functions to use --format yaml. I didn't know that was even an option with list-models. It's definitely a lot cleaner, so thank you for the suggestion. As for why I this uses list-models instead of switch, the bug specifies list-models and I wanted to keep it as close to the original case as possible.