ML Hallucination checker draft

[riya-singh28]

Description

This PR adds the following:

1. Fixes the ReactionStepFeaturizer to make it compatible with all the Deepchem Featurizers.
2. HallucinationChecker class Inference infrastructure for detecting pathway hallucinations using either rule-based heuristics or unified machine learning models. This class replaces the resolve_hallucination function in hallucination_helpers.py in the autosolve branch.
3. HallucinationTrainer class is a DeepChem-based ML infrastructure for training models to detect hallucinations.
4. Added utility functions to the hallucination_utils.py

I have added the example.py for review. I will add it to the docs later. Working on cleaning up the tests.

Fix #(issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
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• Documentations (modification for documents)

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New unit tests pass locally with my changes
• I have checked my code and corrected any misspellings