Remove explicit nuget references

## Ask a question

With the consolidation of TFMs to a single net6.0 target, can the explicit references to some nuget packages be removed without offending any security scanner?

I tried removing the references to these packages
* `System.Security.Cryptography.X509Certificates`
* `System.Private.Uri`
* `System.Configuration.ConfigurationManager`
* `NuGet.Packaging`
* `System.Collections.Immutable`

and ran this command
`dotnet list .\All.sln package --vulnerable --include-transitive`
which didn't report any vulnerabilities.

One potential downside of removing dependencies again is that it can break re-compilation if someone already started relying on that Scaffolding includes certain nugets.