ajout des docstring des fonctions de test

tests/api/test_api_absences.py

tests/api/test_api_departements.py

tests/api/test_api_etudiants.py

tests/api/test_api_evaluations.py

tests/api/test_api_formations.py

tests/api/test_api_formsemestre.py

tests/api/test_api_jury.py

tests/api/test_api_partitions.py

tests/api/test_api_permissions.py