message: fix LightManager::forEachComponent()
  the Instance id was off-by-one and didn't match the
  given entity.
  in gltf_viewer this caused contact shadows to not work
  when there was only a single directional light
diff: @@ -753,7 +753,8 @@ public:
  void forEachComponent(F func) noexcept {
  utils::Entity const* const pEntity = getEntities();
  for (size_t i = 0, c = getComponentCount(); i < c; i++) {
  - func(pEntity[i], Instance(i));
  + // Instance 0 is the invalid instance
  + func(pEntity[i], Instance(i + 1));
  }
  }
  };
  