fix: write nan values when sector data is not given

[doneachh]

Closes # (if applicable).

Changes proposed in this Pull Request

When no sector data is given for a country, we write nan values into base_energy_totals.csv instead of ignoring it.

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, config.tutorial.yaml, and test/config.test1.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.

[doneachh]

@energyLS i deleted a line in prepare_energy_totals, which dropped all lines with nan values as well to keep the keys. But in the next line na values get replaced by 0. Considering whether thats ok or to delete the line with replacing na by 0s as well. What do you think? :)

[energyLS]

@energyLS i deleted a line in prepare_energy_totals, which dropped all lines with nan values as well to keep the keys. But in the next line na values get replaced by 0. Considering whether thats ok or to delete the line with replacing na by 0s as well. What do you think? :)

@doneachh so basically we get zeros everywhere where you have introduced nans?

[doneachh]

@energyLS i deleted a line in prepare_energy_totals, which dropped all lines with nan values as well to keep the keys. But in the next line na values get replaced by 0. Considering whether thats ok or to delete the line with replacing na by 0s as well. What do you think? :)

@doneachh so basically we get zeros everywhere where you have introduced nans?

Yes