[pudbev lister] use alternative packages list endpoint
Feedback from public review :
pub.dev community suggests to use https://pub.dev/api/package-names instead of https://pub.dev/api/packages (unofficial, will be deprecated soon)
see https://github.com/dart-lang/pub-dev/issues/6111#issuecomment-1293392619 for more info
Migrated from T4665 (view on Phabricator)