Fixes reset_joints_by_scale and reset_joints_by_offsets to only affect the joint_names specified in SceneEntityCfg (#2899)

# Description

Both reset_joints_by_offsets and reset_joints_by_scale ignores the
joint_ids specified in SceneEntityCfg passed through asset_cfg and
affects all joints.

This bug is affecting all cartpole environments. 

After the fix the functions are restricted to only reset the joint
specified through SceneEntityCfg, Cartpole environment runs and reset
behaves correctly

Fixes #2800 #980 #1742 

## Type of change

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- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] 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
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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