Microsoft.CodeAnalysis.LanguageServer NuGet Package shouldn't have transitive dependencies

As per this comment. If you try to 'restore' the language server package you'll likely run into issues with lots of dependencies and them not existing in public feeds.

As the language server package should be a self-contained glorified zip folder, they should be configured to not have dependencies listed.

> These packages aren't 'normal' NuGet packages in the sense they are really just glorified .zips to copy around the final built images. They shouldn't really have any dependencies in the first place. @thomhurst can you file a bug for this and we'll just remove them entirely?

_Originally posted by @jasonmalinowski in https://github.com/dotnet/roslyn/discussions/79192#discussioncomment-13620953_