Remove _ignore_mandatory_args from FontbakeryCallable
Remove _ignore_mandatory_args from FontbakeryCallable

It was a leftover from legacy specs. See
https://github.com/googlefonts/fontbakery/issues/1910

moyogo/fontbakery,moyogo/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,googlefonts/fontbakery