script: fix state of script plugins when list of scripts has not been downloaded

The problem happened when doing "/script load script.py" if the scripts list
has not been downloaded (with "/script update"): WeeChat displays that python
plugin is not loaded (which is wrong).

src/plugins/script/script-action.c

@@ -1147,6 +1147,8 @@ script_action_run ()
     if (!script_actions)
         return 0;
 
+    script_get_loaded_plugins ();
+
     actions = weechat_string_split (script_actions, "\n", 0, 0, &num_actions);
     if (actions)
     {