Chrome is always used, regardless of default browser

Created by: rmccue

openBrowser always attempts to open Chrome on macOS, even when Firefox is set as the default browser.

It does check the BROWSER env var, but given that this isn't set by default when setting a default browser, it's not authoritative. Instead, openBrowser assumes that if Chrome is open, it's fine to use. For developers who have multiple browsers open, this is not the case, and the behaviour is confusing.

Instead, it would be great if the preferences could be checked first, perhaps using default-browser?