Clean up font declarations

re: fish-shell/fish-shell@2726712e01f2ca254bd46deb5bd27cd417fca158

As this is rendering ok in Firefox, this version should pickup the best
fonts for most browser/os variants based on 'font-stretch' support.

`.fish_left_bar` should be condensed, the main body font shouldn't.
Make fish config work if one of colors is undefined.

This moves the sorting to be done before sorting remaining colors.