Fix circular dependencies between population and faostat_rl

[pabloarosado]

I wanted to archive the old FAOSTAT steps (version 2024-03-14) now that we have a version 2025-03-17. However, there is still one use of faostat_rl that can't be updated, and that's our population dataset (step garden/demography/2024-07-15/population). This dependency cannot be upgraded, because we enter a circular dependency:

• Our population dataset includes population density, for which it uses land area from FAOSTAT RL dataset.
• However, the FAOSTAT RL dataset has per capita indicators, for which it uses population.