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/evalfunc.c b/src/evalfunc.c
index c4abfdd..4456f69 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -4105,7 +4105,7 @@
 
 	if (p_verbose == 0)
 	    ++emsg_off;
-	result = eval_vars(s, s, &len, NULL, &errormsg, NULL);
+	result = eval_vars(s, s, &len, NULL, &errormsg, NULL, FALSE);
 	if (p_verbose == 0)
 	    --emsg_off;
 	else if (errormsg != NULL)