[Refactor] Use early returns in custom-oclif-loader runCommand

[gonzaloriestra]

This PR refactors runCommand inside packages/cli-kit/src/public/node/custom-oclif-loader.ts to replace deeply nested conditional if blocks with cleaner early returns. All unit tests, type-checking, and lint checks pass successfully.

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PR created automatically by Jules for task 1152039811017029117 started by @gonzaloriestra

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