feat(iorails): Support blocking rails

[tgasser-nv]

Description

Related Issue(s)

Verification

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Checklist

• I've read the CONTRIBUTING guidelines.
• This PR links to a triaged issue assigned to me.
• My PR title follows the project commit convention.
• I've updated the documentation if applicable.
• I've added tests if applicable.
• I've noted any verification beyond CI and any checks I couldn't run.
• I did not update generated changelog files manually.
• I addressed all CodeRabbit, Greptile, and other review comments, or replied with why no change is needed.
• @mentions of the person or team responsible for reviewing proposed changes.

[codecov]

Codecov Report

❌ Patch coverage is 97.70115% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
nemoguardrails/guardrails/compiled_rail.py	97.40%	2 Missing ⚠️

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