Stop publishing the Microsoft.NET.Build.Containers package when the SDK is released

[baronfel]

Is your feature request related to a problem? Please describe.

Now that the containers package is fully integrated into the SDK, there's no reason for the package to be published anymore. In fact, it can lead to end-user errors when they use e.g. an 8.0 SDK and update to the 9.0 version of the package - because the tasks target net9.0 and there's no information for NuGet to see that would stop the package from working on .NET 8, NuGet happily lets users update.

Describe the solution you'd like

We should stop publishing the package, but continue embedding it into the .NET SDK.
The existing check to warn users to not use the package should be kept.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[baronfel]

When we do this we'll want to update the learn.ms.com docs for container publish as well.