fix(yarn): no longer error on pnp (#5009)
### Description
Fixes #4953
We had unintentionally dropped the PnP check in Go and reintroduced the
check in Rust. This PR simply removes this check and returns us to the
old unintentional behavior. I believe run should work as expected since
we execute all tasks via `yarn` which automatically does the right thing
with `.pnp.cjs`. (Also #4953 contains many reports of people using Yarn
PnP with turbo just fine)
This PR does not:
- Add support for PnP with prune. That check was never accidentally
dropped and I want to do a few more tests before enabling that.
- Fixup our examples to work correctly with Yarn PnP. All of the ones I
tried required adding some dependencies
Reviewer notes:
I apologize, but I ended up fixing all the clippy lints in the files I
touched and not just the ones introduced from the behavior change. This
resulted in the PR being larger than necessary.
### Testing Instructions
Existing unit tests around yarn/berry detection now pass without the a
`.yarnrc.yml` specifying `nodeLinker: node-modules`. Manual testing of
some test repos
Co-authored-by: Chris Olszewski <Chris Olszewski>
