The fix for T75936 made it possible to export invisible objects to Alembic. This commit applies the same approach to the USD exporter. The USD and Alembic code is slightly different in terms of where in the exported file the visibility attribute is stored. In USD the visibility is used to prune the scene graph, and thus there are only two options: "hidden" and "inherited". Setting the visiblity of a node in the scene graph to "hidden" immediately hides all its children. To allow hidden parents with visible children, the visibility is stored on the object data (so the geometry/camera/lamp/etc) instead.