Remove extraneous <span>s from StateLabel

[shawnbot]

After reimplementing StateLabel in https://github.com/github/github/pull/96992, @jonrohan and I noticed that there's no need for the fussy <span> logic that we do for instances with icons and children. In other words, this function and this statement should go away, then this line should change to {icon}.

[emplums]

Heya @shawnbot I was looking into this one today - and I think we do need this logic - only injecting the {icon} in the component results in this - we need that extra margin to space the icon and the text

[emplums]

We could do this with a space instead:

{icon} {children} but that creates the <!-- --> weird spacing thing we were seeing on primer.style

[shawnbot]

Dang @emplums, that's a bummer. I guess we could also use our internal Octicon component and pass it something like mr={children ? 2 : 0} instead?