Core/Movement: Fix stunned falling units freezing the client (#24000)

(cherry picked from commit 8f94c9ef6b843f69d014b7e3a4b3b30e5d1515e4)

src/server/game/Movement/MotionMaster.cpp

@@ -961,7 +961,7 @@ void MotionMaster::MoveFall(uint32 id/* = 0*/)
         return;
 
     // rooted units don't move (also setting falling+root flag causes client freezes)
-    if (_owner->HasUnitState(UNIT_STATE_ROOT))
+    if (_owner->HasUnitState(UNIT_STATE_ROOT | UNIT_STATE_STUNNED))
         return;
 
     _owner->SetFall(true);