Treat empty `RootCollisionNode` in NIF as NC flag and generate VisualOnly collision shape
Resolves #6841 (closed) (the bug "3rd person camera doesn't collide with tapestries" that wasn't fully fixed by !1516 (merged))
Edited by Petr Mikheev
Resolves #6841 (closed) (the bug "3rd person camera doesn't collide with tapestries" that wasn't fully fixed by !1516 (merged))