Under WSL, `PATH` can include a Windows Node install, so `command -v npm` can find its `npm` shell shim, which then failed against Windows paths.
That npm is not a system node that nvm would shadow, so under WSL, skip an npm that has an `npm.cmd` beside it: both the Node installer and npm's own shims put one there.
Outside WSL (eg, Git Bash or Cygwin), a Windows npm is the system node, so the warning is kept.
Fixes#3700.
Signed-off-by: NUAAwqy <146524024+NUAAwqy@users.noreply.github.com>
Co-Authored-By: Codex <noreply@openai.com>