bundle/krew: use kubectl-krew directly

[branchv]

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A kubectl extension is just a kubectl-* executable on PATH, so we can simplify a bit here and just invoke kubectl-krew directly

[Copilot]

Pull request overview

A kubectl plugin is just a kubectl-* executable on PATH, so this PR simplifies the Krew bundle extension by locating and invoking kubectl-krew directly instead of going through kubectl krew …. This removes the need for the separate package_manager_installed? probe (which previously shelled out to kubectl krew version) and lets the base class's executable-presence check do the work.

Changes:

• Switch package_manager_executable lookup from kubectl to kubectl-krew.
• Drop the custom package_manager_installed? override and its @krew_installed cache.
• Update packages and install_package! to call the kubectl-krew binary without the "krew" subcommand argument.

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[MikeMcQuaid]

Thanks! A few questions.

[MikeMcQuaid]

Thanks!