fetchYarnDeps: fix by deduplicating requests (#336784)

	return Promise.all(workers)

}

// This could be implemented using [`Map.groupBy`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/groupBy),

// but that method is only supported starting with Node 21

const uniqueBy = (arr, callback) => {

	const map = new Map()

	for (const elem of arr) {

		map.set(callback(elem), elem)

	}

	return [...map.values()]

}

const prefetchYarnDeps = async (lockContents, verbose) => {

	const lockData = lockfile.parse(lockContents)

	await performParallel(

		Object.entries(lockData.object)

		uniqueBy(Object.entries(lockData.object), ([_, value]) => value.resolved)

		.map(([key, value]) => () => downloadPkg({ key, ...value }, verbose))

	)

	await fs.promises.writeFile('yarn.lock', lockContents)