Test uninstalling casks

[MikeMcQuaid]

Add regression test to catch failures like #23086 again.

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[Copilot]

Pull request overview

Adds a regression integration test to ensure brew uninstall correctly handles uninstalling a Cask specified by file path (alongside an existing Formula uninstall scenario), aiming to prevent future failures of path-based Cask uninstalls.

Changes:

• Extends the existing uninstall integration test to install a fixture Cask via a path under a tap and then uninstall it via a path.
• Asserts both uninstall output and that installed artifacts (app bundle + caskroom state) are removed.

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