Fire 'ext.echo.badge.countChange' after DOM changes
Fire 'ext.echo.badge.countChange' after DOM changes

The event should fire after the count actually changes in the
DOM as well as the internal workings of Echo.

Change-Id: I03f1742b209305080af8784632f07dff63135d81

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo