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This change updates the Isaac-PickPlace-GR1T2-Abs-v0 env to use a
steering wheel asset instead of a metal rod. The steering wheel asset is
easier to grasp.

Changes:

1. Update Isaac-PickPlace-GR1T2-Abs-v0 to use steering wheel asset
2. Update Mimic docs to reflect the change

Fixes # (issue)

Fixes poor graspability of the object once it falls in the
Isaac-PickPlace-GR1T2-Abs-v0 env.

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- New feature (non-breaking change which adds functionality)
- This change requires a documentation update

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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---------
Signed-off-by: Kelly Guo <kellyguo123@hotmail.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>