Add a post_package_info hook to check whether cpp_info.libs is empty if there is a shared option

[SpaceIm]

Refer to https://github.com/conan-io/conan-center-index/pull/15932#issuecomment-1427012456

There might be a pernicious issue in recipes where cpp_info.libs is an empty list while it should not (basically it may happen when relying on collect_libs()), and current hooks are tricked.