Fix expansion of globs that contain a ~USER reference

Fix expansion of globs that contain a ~USER reference

This regressed from the fix to bug#28064, and was discovered here:
<https://lists.gnu.org/archive/html/bug-gnu-emacs/2023-03/msg01744.html>.

* lisp/eshell/em-dirs.el (eshell-expand-user-reference): Let FILE be a
list, and move the implementation to...
(eshell-expand-user-reference-1): ... here.

* lisp/eshell/em-glob.el (eshell-add-glob-modifier): Remove special
handling for expanding user references; it's better to keep it in
"em-dirs.el".