fix: Cycle detection bug in MONDO ontology

[berntpopp]

Description:

There is a bug in the get_ontology function related to MONDO where a cycle is detected. The error occurs within the ancs_from_pars function, causing the process to fail. This needs investigation and resolution.

Error message:
```
Error in ancs_from_pars(int.parse, int.child, is) :
Cycle detected in ontology! See ancestors of;
```

Tasks:

• Investigate the root cause of the cycle detection issue in MONDO.
• Implement a solution to handle cycles in the ontology structure gracefully.
• Add tests to ensure cycles are handled properly in future.
• Update documentation with any relevant details.

Rationale:
Fixing this bug is crucial to ensure that ontology-based functionalities work correctly without crashing due to cycles in the ontology.