Corrupted STL file

Hi, these STL files contain only null bytes, and are referenced in their urdf files, which generate errors when used in a simulator:
- urdf_files/matlab/kortex_v12_description/arms/gen3/7dof/meshes/end_effector_link.STL
- urdf_files/matlab/kortex_description/meshes/EndEffector_Link.STL
