DOT abilities damage barriers when target is untargetable/invincible

[yackback]

If Lady Geist uses life drain on an opponent that then becomes untargetable/invincible, then, if a barrier is up, Life Drain will continue to damage the barrier.
The same is true for (at least) Pocket Affliction DOT and Infernus Flame Dash.

Tested in Sandbox with both Ethereal Shift and Pocket's suitcase while either Spirit Shielding or Reactive Barrier was up.