fix(Presence): prevent position rewind when body physics collisions off
fix(Presence): prevent position rewind when body physics collisions off

If the Body Physics script is present and the enable collisions is
disabled, then prevent a position rewind from happening as it probably
means the user is wanting to clip inside geometry.

If no Body Physics script is present then it will always rewind.

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