Window inactive/active border color token is applied to all windows

[miguelsolorio]

When you set window.inactiveBorder it applies the border to all windows:

This feels like a bug because the active window should never have the border because it's not inactive. If we we're worried about the border popping in/out when only setting one we could look into using a transparent border like:

I think anyone who tries to use this color token would easily be confused.

[JacksonKearl]

Now it looks like setting window.inactiveBorder also set's window.activeBorder to #fff. This seems wrong to me, I don't know other places where customizing one token adds a different token? Could either the the inactive border be inset (and no activeBorder applied), or the auto-applied activeBorder be transparent? It looks particularly out of place in our default light theme, for example:

[JacksonKearl]

Similar in Windows:

[eamodio]

The border being added is actually transparent -- so you are seeing the background color coming through. This is why I originally had either color fallback to the other. Because there isn't a good way to handle this without turning off the border altogether which causes a full-layout flash (which is not a good experience imo)