Handle CV1 headband LEDs

[thaytan]

Because the headband is articulated, the LEDs at the back of the headset are not where the 3D model says they should be, and matching pose yields the wrong orientation.

One idea would be to split out and track those LEDs as a separate sub-device from the main headset and extract a relative pose that translates from the main headset LEDs to the headband. Whenever both the headset and the headband are visible simultaneously, the conversion pose could be updated.

A quicker thing to do would be to ignore them entirely so they at least don't make anything worse.

[thaytan]

I added a hack in fac815b to ignore headband LEDs entirely for now by filtering them from the 3D model.