fix(PlayerPresence): prevent crash when ignoring inactive colliders
fix(PlayerPresence): prevent crash when ignoring inactive colliders

There is a known issue with Unity that if a collider is inactive but
IgnoreCollisions is called on it then it can cause unity to crash.

This fix addresses that by checking if the collider is active before
attempting to ignore collisions.

gpvigano/VRTK,Innoactive/IA-unity-VR-toolkit-VRTK,adamjweaver/VRTK,TMaloteaux/SteamVR_Unity_Toolkit,pargee/SteamVR_Unity_Toolkit,gpvigano/SteamVR_Unity_Toolkit,gomez-addams/SteamVR_Unity_Toolkit,nmccarty/htvr,virror/VRTK,red-horizon/VRTK,Blueteak/SteamVR_Unity_Toolkit,thestonefox/VRTK,Fulby/VRTK,mattboy64/SteamVR_Unity_Toolkit,thestonefox/SteamVR_Unity_Toolkit