patch 8.2.4841: empty string considered an error for expand()

Problem:    Empty string considered an error for expand() when 'verbose' is
            set. (Christian Brabandt)
Solution:   Do not give an error for an empty result. (closes #10307)
diff --git a/src/filepath.c b/src/filepath.c
index 6ee5fad..09c9f4a 100644
--- a/src/filepath.c
+++ b/src/filepath.c
@@ -3097,7 +3097,7 @@
     {
 	++emsg_off;
 	eval_pat = eval_vars(exp_pat, exp_pat, &usedlen,
-						    NULL, &ignored_msg, NULL);
+					       NULL, &ignored_msg, NULL, TRUE);
 	--emsg_off;
 	if (eval_pat != NULL)
 	    exp_pat = concat_str(eval_pat, exp_pat + usedlen);