Core/Movement: Prevent rooted units from falling

* Fixes a client freeze

Closes #23042

src/server/game/Movement/MotionMaster.cpp

@@ -581,6 +581,10 @@ void MotionMaster::MoveFall(uint32 id /*=0*/)
     if (std::fabs(_owner->GetPositionZ() - tz) < 0.1f)
         return;
 
+    // rooted units don't move (also setting falling+root flag causes client freezes)
+    if (_owner->IsRooted())
+        return;
+
     _owner->AddUnitMovementFlag(MOVEMENTFLAG_FALLING);
     _owner->m_movementInfo.SetFallTime(0);