fix: handles possible NpmDetails array (W-24124675)

[jfeingold35]

@W-24124675@

Closes #917

Explanation: In NPM v12, npm view has been changed to always return an array. As such, one method in version.ts had to be changed to handle the possibility of receiving an array from npm view.

Test coverage is absent due to the difficulty of testing a problem that is dependent on an npm view result returned by a child process, but manual testing was performed.

TO VALIDATE FIX:

sf plugins uninstall @oclif/plugin-version // make sure you're using the production plugin

npm install --global npm@latest // v12.0.1 at time of writing
sf version --verbose // Observe error

npm install --global npm@11.19.1 // latest v11 release
sf version --verbose // observe success

git checkout [this branch]
yarn && yarn build
sf plugins link . // Use the fixed plugin
npm install --global npm@latest
sf version --verbose // observe success
npm install --global npm@11.19.1
sf version --verbose // observe success