patch 8.2.4869: expression in command block does not look after NL

Problem:    Expression in command block does not look after NL.
Solution:   Skip over NL to check what follows. (closes #10358)
diff --git a/src/vim9script.c b/src/vim9script.c
index b1bfe63..6595882 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -589,7 +589,7 @@
 	char_u *p;
 
 	if (getnext)
-	    arg = eval_next_line(evalarg);
+	    arg = eval_next_line(expr_end, evalarg);
 	else
 	    arg = nextarg;