base-setup fails if packageManager is set

[fcollonval]

Description

Run CACHE_DIR=$(yarn config get cacheFolder)
error This project's package.json defines "packageManager": "yarn@^3.5.0". However the current global version of Yarn is 1.22.22.

Presence of the "packageManager" field indicates that the project is meant to be used with Corepack, a tool included by default with all official Node.js distributions starting from 16.9 and 14.19.
Corepack must currently be enabled by running corepack enable in your terminal. For more information, check out https://yarnpkg.com/corepack.

Reproduce

Error seen in https://github.com/jupyterlab-contrib/jupyterlab-variableInspector/actions/runs/9548170411/job/26314738625?pr=304

Expected behavior

No error