[Refactor] Simplify control flow in getListOfTunnelPlugins

[gonzaloriestra]

WHAT is this pull request doing?

Refactors getListOfTunnelPlugins in packages/cli-kit/src/public/node/plugins.ts to improve control flow clarity by extracting duplicate check result to hasDuplicates variable and using explicit block guard clause.

How to test your changes?

CI

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PR created automatically by Jules for task 15801288451020594469 started by @gonzaloriestra

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