Always disable Airplane Mode when using WP-CLI

Scenario: I'm on a slow connection so I have airplane mode enabled. I then decide to install a plugin via `wp plugin install foo-plugin`, but it fails due to airplane mode blocking the API request. I need to navigate to the site, disable airplane mode, re-run the command, then re-enable airplane mode.

I think it's fairly safe to just disable airplane mode whenever WP-CLI is being used. This patch does that.

Any objections?