chore: remove `devEngines` declaration in root package (#32398)

This change removes the `devEngines` declaration in the root package. It
didn't match the package.json spec and in npm 10.9.0 (released in
October), a breaking change was introduced that checks the `devEngines`
property. This causes `npm pack` calls to fail, due to the malformed
`devEngines`. Since there's already an `.nvmrc` defined in the repo, and
no strong need to enforce a specific node version for local development,
this removes the declaration altogether.