PoseCostMetric offset_position parameter doesn't respect negative values

[KySmith1]

1. cuRobo installation mode (choose from [python, isaac sim, docker python, docker isaac sim]):
   Docker Python (nvcr.io/nvidia/pytorch:23.12-py3]
2. python version:
   Python 3.10
3. Isaac Sim version (if using):
   N/A (Not in use)

CuRobo Version:
0.7.6. Also tested in 0.7.4.

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Issue Details

When specified, pose cost metric offset positions are not accepting negative values. As a result, the resultant motions are always in the "positive" direction with respect to the URDF coordinate frame. For example:

    plan_config.pose_cost_metric = PoseCostMetric(
        hold_partial_pose=True,
        hold_vec_weight=tensor_args.to_device([1.0, 1.0, 1.0, 1.0, 1.0, 0.0]),
        offset_position=tensor_args.to_device([0.0, 0.0, 0.4]),
        offset_tstep_fraction=0.55,
    )

Screencast.from.2024-12-19.13-13-28.webm

This is expected, but the result is the same if the following is provided:

    plan_config.pose_cost_metric = PoseCostMetric(
        hold_partial_pose=True,
        hold_vec_weight=tensor_args.to_device([1.0, 1.0, 1.0, 1.0, 1.0, 0.0]),
        offset_position=tensor_args.to_device([0.0, 0.0, -0.4]),
        offset_tstep_fraction=0.55,
    )

It would be expected for the final pose to be below the partial pose on the Z axis. At the moment, it doesn't appear to be possible to have the final pose be below the partial pose with the current API.