# Description

This PR adds `NoiseModel` support for manager-based workflows. To
achieve this, I have:
- Added `NoiseModel` lifecycle management to `ObservationManager`.
- Added a `Callable` field, `func`, to `NoiseModelCfg`, which
`ObservationManager` uses to assign the class instance within, similar
to how it is done for `ModifierBase`.
- Renamed `apply()` to be `__call()__`, to be consistent with
function-based noises and `ModifierBase`.

Fixes #2715 and #1864.

Note: I left the changelog with the entry [Unreleased] until the PR is
given the green light.

## Type of change

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

## Checklist

- [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
- [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