Minor bug fixing during country-wise sensitivity

[davide-f]

Closes # (if applicable).

Changes proposed in this Pull Request

Various (hopefully) minor fixes to make the country-wise analysis work.
The country-wise analysis will be performed using:

• force_ac: true
• drop all isolated buses (p_threshold_drop_isolated = 100_000 MW)
• number of clusters: the minimum between 5 clusters and the number of buses of the country

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Newly introduced dependencies are added to envs/environment.yaml and envs/environment.docs.yaml.
• Changes in configuration options are added in all of config.default.yaml and config.tutorial.yaml.
• Add a test config or line additions to test/ (note tests are changing the config.tutorial.yaml)
• Changes in configuration options are also documented in doc/configtables/*.csv and line references are adjusted in doc/configuration.rst and doc/tutorial.rst.
• A note for the release notes doc/release_notes.rst is amended in the format of previous release notes, including reference to the requested PR.