patch 8.2.4040: keeping track of allocated lines is too complicated

Problem:    Keeping track of allocated lines in user functions is too
            complicated.
Solution:   Instead of freeing individual lines keep them all until the end.
diff --git a/src/message.c b/src/message.c
index 17c541f..04a51fb 100644
--- a/src/message.c
+++ b/src/message.c
@@ -587,7 +587,7 @@
     if (STRCMP("RESET", error) == 0)
 	ga_clear_strings(&ignore_error_list);
     else
-	ga_add_string(&ignore_error_list, error);
+	ga_copy_string(&ignore_error_list, error);
 }
 
     static int