Change from link_pose to link_poses

[tylerlum]

I believe link_poses is always a Optional[Dict[str, Pose]]. Although Pose could technically be 1 or N poses, a dict of these should probably always be plural. This name change reduces confusion about link_pose and link_poses appearing to be different

This happens often, but isn't super clear to new users.

    link_poses = state.link_pose

However, this is a breaking change, so might not be worth the switch

[balakumar-s]

Instead of changing which would break existing code that depends on cuRobo, this will be added as an additional api in the next release.