config: add unit tests executions

[finozzifa]

Changes proposed in this Pull Request

The PR proposes the inclusion of unit test runs in the ci.yaml file.

Checklist

• Code changes are sufficiently documented; i.e. new functions contain docstrings and further explanations may be given in doc.
• Data source for new technologies is clearly stated.
• Newly introduced dependencies are added to environment.yaml (if applicable).
• A note for the release notes doc/release_notes.rst of the upcoming release is included.
• I consent to the release of this PR's code under the GPLv3 license.

[lkstrp]

As discussed and just for the sake of completeness:
We can merge this once the gh runner conda env/ pytest issue is resolved. But maybe also a good idea to not waste time on it and set it up with pip/ uv instead

[lkstrp]

🚀