reject mismatched corepack and detected package managers

[EndangeredMassa]

When corepack is used and the package manager or version does not match the inferred package manager or version from the lockfile, we should throw an error. Right now, this can happen with pnpm (for example) where pnpm only logs a warning, causing indeterministic builds.

This PR mostly updates getPathOverrideForPackageManager to not care about corepack, allowing the calling code to compare the detected values to the corepack values.

[changeset-bot]

🦋 Changeset detected

Latest commit: 5a1aa63

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 7 packages

Name	Type
@vercel/build-utils	Patch
vercel	Patch
@vercel/client	Patch
@vercel/gatsby-plugin-vercel-builder	Patch
@vercel/node	Patch
@vercel/static-build	Patch
@vercel-internals/types	Patch

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[EndangeredMassa]

suggestion (blocking): change test setup

The packageJsonPackageManager value is only used if corepack is enabled. Because corepack is not enabled for this test, the lockfile is used to determine the pnpm version, which would be pnpm@6 in this case. The test description here implies it would be pnpm@7.

This test is currently testing that having a packageJsonPackageManager doesn't change the result, which is also a useful test, but doesn't match the description.

I think we should walk through these tests together to make sure we testing the different conditions we need.‏