Remove Packages::Npm::PackagePresenter

What does this MR do and why?

This MR removes Packages::Npm::PackagePresenter since it doesn't bring anything meaningful after Extract npm metadata generation from a presenter (!114450 - merged) was merged and only "converts" a hash to an instance of ruby class.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

1. Create a package

   def fixture_file_upload(*args, **kwargs)
     Rack::Test::UploadedFile.new(*args, **kwargs)
   end
   
   project = FactoryBot.create(:project, :public)
   
   package = FactoryBot.create(:npm_package, project: project, name: "test")
   
   FactoryBot.create(:packages_tag, package: package, name: "my-tag")

2. Call the updated endpoints to check if everything works correctly.

   Package's metadata endpoint:

   $ curl "http://gdk.test:3000/api/v4/projects/<project-id>/packages/npm/test"

   Package's list tags endpoint:

   $ curl "http://gdk.test:3000/api/v4/projects/<project-id>/packages/npm/-/package/test/dist-tags" 

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #414611 (closed)