Improve enumitem support

[eg9]

The package mentions twice enumitem: in the macro \GTS@DisablePredefinedCmds it does

  \let\enit@format\@empty % package enumitem

and in \GTS@PredefinedLeftCmds it does

  \GTS@TestLeft\enit@format\GTS@Cdr % package enumitem

In both places also \enit@align should be added, because it can end up in the label.

Source: https://tex.stackexchange.com/q/526125/4427