Fix industrial demand for ammonia when endogenously modelled

[koen-vg]

In calculating industrial energy demand today, demand for ammonia must be resolved into just "ammonia" when endogenously modelled, or into electricity and hydrogen if not. Before this fix, energy demand for ammonia was double-counted at current and near-term planning horizons when sector['ammonia'] = True; both in terms of ammonia and in terms of electricity and hydrogen.

While not incredibly large in magnitude, hydrogen demand at 2025 planning horizon was essentially double what it should have been before this fix.

Checklist

• [x] I tested my contribution locally and it works as intended.
• [ ] Code and workflow changes are sufficiently documented.
• [ ] Changed dependencies are added to envs/environment.yaml.
• [ ] Changes in configuration options are added in config/config.default.yaml.
• [ ] Changes in configuration options are documented in doc/configtables/*.csv.
• [ ] Sources of newly added data are documented in doc/data_sources.rst.
• [x] A release note doc/release_notes.rst is added.

[fneum]

Great! I'll do a small follow-up so that tests for Windows and MacOS run through (the snakemake object is lost in the multiprocessing). The dev test is failing because of some breaking changes in powerplantmatching that need to be addressed in PyPSA-Eur, so that's ok.