fix for #65704. offline status indicators aren't changing.

now the offline indicators in multiple browser, mailnews, msg compose, editor windows will
update when we go offline.  also, allow windows to 'jump in' before the offline state
changes so they can do certain tasks and allow the user to cancel the state change, if needed.
(important for mailnews).  there is still some work to do, but this is the bulk of it.
r=alecf (on initial patch), r=bienvenu, sr=ben.

suite/browser/navigator.js

@@ -247,8 +247,6 @@ function Startup()
 
   // Do all UI building here:
 
-  setOfflineStatus();
-
   // set home button tooltip text
   var homePage = getHomePage();
   if (homePage)