You could add an ErrorLevelFeedbackMessageFilter to your FeedbackPanels (there is a constructor accepting one). If you create the filter based on your deployment mode, this should be what you need.
In Detail:
Change your new FeedbackPanel("id")
to new FeedbackPanel("id", Application.getFeedbackMessageFilter())
and implement this method as
public IFeedbackMessageFilter getFeedbackMessageFilter() {
IFeedbackMessageFilter filter = null;
if (RuntimeConfigurationType.DEVELOPMENT.equals(getConfigurationType())) {
filter = new ErrorLevelFeedbackMessageFilter(FeedbackMessage.DEBUG);
} else {
filter = new ErrorLevelFeedbackMessageFilter(FeedbackMessage.ERROR);
}
return filter;
}