texlive: provide bin.texlive on Darwin too
texlive attribute was accidentally added in attrset wrapped with
stdenv.lib.optionalAttrs (!stdenv.isDarwin)
Fixes: dbc2c1c4b8 ('texlive: add missing perl dependencies for latexindent')
(cherry picked from commit b6d0bdf5136031b49d174e638e7d0bdc8c5e5a12)
