Move setup step to init in `Abiotic` and `AbioticSimple` models

[dalonsoa]

Description

It was done already for the Hydrology model but I forgot to do the same for the other two. The main changes have more to do with fixing the tests than the actual change in the code.

Fixes # N/A

Type of change

• [x] New feature (non-breaking change which adds functionality)
• [ ] Optimization (back-end change that speeds up the code)
• [ ] Bug fix (non-breaking change which fixes an issue)

Key checklist

• [x] Make sure you've run the pre-commit checks: $ pre-commit run -a
• [x] All tests pass: $ poetry run pytest

Further checks

• [x] Code is commented, particularly in hard-to-understand areas
• [x] Tests added that prove fix is effective or that feature works
• [ ] Relevant documentation reviewed and updated

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.98%. Comparing base (7ce59b2) to head (997f395).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #524 +/- ## ======================================== Coverage 94.97% 94.98% ======================================== Files 74 74 Lines 4141 4145 +4 ======================================== + Hits 3933 3937 +4 Misses 208 208 ```

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[davidorme]

@TaranRallings - The animal model also uses a setup method, which is currently also called from within __init__, so runs twice.