Update data fetching for packageVersion.tsx

- Use Dapper's getPackageListingDetails method rather than
  getPackageVersionDetails as the latter may serve rejected content
  which we don't want to show
- SSR loader and clientLoader mimic what their counterparts in
  packageListing.tsx does, namely loader makes the request
  unauthenticated and returns undefined if the response is 404, while
  clientLoader first does an unauthenticated request, and should that
  fail, another one as authenticated. This is done to improve cache
  hits
- Since both loaders now await the responses for listing, it's never
  a promise and lot of the Suspense/Await elements become obsolete

Author: anttimaki