[Fix]: Create new DataModule instance for each optimization trial

[amitsubhashchejara]

Description

Fixed an issue where the DataModule instance was potentially being reused across optimization trials, which could lead to state accumulation and inconsistent results. Now ensures a fresh DataModule instance is created for each hyperparameter evaluation trial.

Related Issues

"Fixes #212"

Type of Change

• [Fix] - Bug fix (non-breaking change fixing an issue)
• [Feature] - New feature (non-breaking change adding functionality)
• [Refactor] - Code refactoring (no functional changes)
• [Release] - Release preparation
• [Hotfix] - Critical fix for production

Checklist

• PR title includes appropriate tag: [Fix], [Feature], [Refactor], [Release], or [Hotfix]
• Linked to related issue (if applicable)
• Code passes make check (lint, format, isort)
• Tests added/updated for changes (if applicable)
• Documentation updated (if applicable)

Testing

The changes can be verified by:

1. Running the existing test suite for TorchExperiment
2. Testing with a custom DataModule that logs instantiation - verify new instance created per trial
3. Running multiple optimization trials and checking for consistent behavior

Pre-commit hooks pass successfully.