Add Bandit security linter workflow

[ms-kumar]

This workflow runs Bandit, a security linter for Python, on codebase changes to identify common security issues.

Description

[Describe what this PR does]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Performance improvement
• Other: [Specify]

Testing

[Describe how you tested this change]

Checklist

• Code follows TORML_CODING_GUIDELINES.md
• Estimator API follows scikit-learn-style conventions
• PyTorch is used for numerical backend code
• Tests added or updated
• Documentation updated if public behavior changed
• RELEASES.md updated for user-visible changes

Related Issues

Closes #[issue_number]

[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

• The 'Security' tab will display more code scanning analysis results (e.g., for the default branch).
• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

For more information about GitHub Code Scanning, check out the documentation.