Use 'Enumerate Package Versions' request for NuGet version enumeration

[michaelkedar]

Enumerate Package Versions returns just the array of the versions of a package, as opposed to the endpoint we currently use which lists all the package info (but can also return some batch thing for big queries).

e.g:
Current: https://api.nuget.org/v3/registration5-semver1/newtonsoft.json/index.json
New: https://api.nuget.org/v3-flatcontainer/newtonsoft.json/index.json

[github-actions]

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[github-actions]

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