Focus Tank Button

v1.3

 - Updated TOC to include Mists of Pandaria Classic version 5.5.4.
 - Fixed compatibility with WoW Classic 5.5.4 where clicking the
   Focus Tank button no longer assigned focus to the group's tank.
 - Updated the secure button implementation to use Blizzard's current
   secure click handling, restoring one-click focus functionality.
 - Added informative chat messages when the button cannot assign focus,
   including when not in a group or when no tank role is assigned.
 - Improved button click registration for greater compatibility with
   Blizzard's secure action system.