Allows loading of initialized configs in `load_cfg_from_registry` (#425)

# Description

Fixed the configuration parsing to give an instanced config instead of
just a non-instanced class.

## Type of change

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

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.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 run all the tests with `./orbit.sh --test` and they pass
- [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

---------
Signed-off-by: Nikita Rudin <48368649+nikitardn@users.noreply.github.com>

source/extensions/omni.isaac.orbit_tasks/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.5.4"
+version = "0.5.6"
 
 # Description
 title = "ORBIT Environments"

source/extensions/omni.isaac.orbit_tasks/docs/CHANGELOG.rst

 Changelog
 ---------
 
+0.5.6 (2024-02-21)
+~~~~~~~~~~~~~~~~~~
+
+Fixed
+^^^^^
+
+* Fixed the configuration parsing to support a pre-initialized configuration object.
+
+
 0.5.5 (2024-02-05)
 ~~~~~~~~~~~~~~~~~~
 

source/extensions/omni.isaac.orbit_tasks/omni/isaac/orbit_tasks/utils/parse_cfg.py

@@ -81,11 +81,13 @@ def load_cfg_from_registry(task_name: str, entry_point_key: str) -> dict | Any:
             mod_path = inspect.getfile(cfg_entry_point)
             # load the configuration
             cfg_cls = cfg_entry_point()
-        else:
+        elif isinstance(cfg_entry_point, str):
             # resolve path to the module location
             mod_name, attr_name = cfg_entry_point.split(":")
             mod = importlib.import_module(mod_name)
             cfg_cls = getattr(mod, attr_name)
+        else:
+            cfg_cls = cfg_entry_point
         # load the configuration
         print(f"[INFO]: Parsing configuration from: {cfg_entry_point}")
         if callable(cfg_cls):