Fix/cask on system conditionals infinite loop

[hyuraku]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew lgtm (style, typechecking and tests) with your changes locally?

---

• AI was used to generate or assist with generating this PR. Please specify below how you used AI to help you, and what steps you have taken to manually verify the changes.

---

Fix infinite autocorrect loop in Cask::OnSystemConditionals cop.

audit_macos_version_conditionals was called without allowed_blocks, so when audit_on_system_blocks corrected on_monterey do → if MacOS.version == :monterey inside flight stanzas (postflight, etc.), the next pass would reverse it back to on_monterey do, causing an infinite loop.

The fix passes allowed_blocks: FLIGHT_STANZA_NAMES to audit_macos_version_conditionals, matching the existing pattern used by audit_arch_conditionals.

Also removes the loop: false workarounds and stale FIXME comments from tests.

Fixes the 3 FIXME comments in on_system_conditionals_spec.rb.

[Copilot]

Pull request overview

Fixes an infinite autocorrect loop in the RuboCop::Cop::Cask::OnSystemConditionals cop when handling macOS version conditionals inside flight stanzas, and updates the spec to assert stable autocorrection without workarounds.

Changes:

• Passes allowed_blocks: FLIGHT_STANZA_NAMES to audit_macos_version_conditionals to prevent conflicting corrections within flight stanzas.
• Removes loop: false and associated FIXME comments from the cop’s spec now that autocorrection converges.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Library/Homebrew/rubocops/cask/on_system_conditionals.rb	Ensures macOS version conditional auditing respects flight-stanza exclusions to avoid flip-flop autocorrections.
Library/Homebrew/test/rubocops/cask/on_system_conditionals_spec.rb	Cleans up specs by removing infinite-loop workarounds and confirming stable corrections.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.

[MikeMcQuaid]

Thanks again @hyuraku!