perf(plugin-pnp): remove redundant node check (#5615)

**What's the problem this PR addresses?**
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#824 added a check that throws an
error on Node < 12 if the `.pnp.cjs` path contains spaces, due to an old
bug in Node.

**How did you fix it?**
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Removed the check since the bug has been fixed since Node 12.

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