Monitor and fix spherical joint handling in IsaacLab

[rubengrandia]

Check on simple examples if Kamino's spherical joint is consistent with PhysX / MJWarp.

[rubengrandia]

Testing on the IsaacLab side shows that spherical / ball joints are broken:

• Actuated joints trigger an error due to coordinate and dof size mismatch
• Passive joints can simulate, but are incorrectly handled when setting joint coordinates. They only set the first 3 elements of the quaternion instead of the full 4 coordinates.