Wrong NuGet API response code for package with no versions available

[ssuenaga_1020]

Microsoft's NuGet server API documentation for enumerating package versions says the API response should be 404 when the package source has no versions of the requested package:
https://learn.microsoft.com/en-us/nuget/api/package-base-address-resource#enumerate-package-versions

But ProGet currently returns 200 with an empty array:

{
    "versions": []
}

The documentation doesn't say the 404 should have specific body content, but just for comparison, api.nuget.org returns an XML body:

<?xml version="1.0" encoding="utf-8"?>
<Error>
    <Code>BlobNotFound</Code>
    <Message>The specified blob does not exist.
RequestId:d5844934-501e-000f-5804-f3cb9b000000
Time:2023-09-29T18:43:32.7072199Z</Message>
</Error>

The reason this is an issue for me is because I use the Version Lens extension for VS Code, which currently relies on the documented 404 behavior:
https://marketplace.visualstudio.com/items?itemName=pflannery.vscode-versionlens

[atripp]

Hi @ssuenaga_1020 ,

Thanks for the detailed report; this seems easy enough to fix, so we'll get this addressed in the next maintenance release (2023.20) via PG-2499.

Cheers,
Alana