Bug

Fixes: dotnet/sdk#52278

Description

This code has already been merged into the dotnet VMR, but NuGet.Client doesn't have a backflow configured for the 10.0.2xx branch: dotnet/dotnet#4139

Spectre.Console's AnsiConsole will send VT commands on initialzation, which breaks formatting of other parts of the dotnet CLI when it expects that the terminal has default settings. So, only initialize AnsiConsole when it's about to be used.

Tests were not added because testing this is very difficult. You can't test using a child process or redirecting to a file, because Spectre detects that the output is being redirected about avoids sending the VT commands. In order to test, we'd need to P/Invoke operating system specific APIs to open a new PTY. We'd then need all new child process test infrastructure to capture the output. If we just wanted to make sure that the VT command that Spectre sends on init isn't sent, we'd need to first figure out what VT command that is, but then searching for it in the output should be simple enough. However, if we wanted to validate that dotnet --info's output isn't being malformed, then we'd need to implement a lot of a terminal emulator to figure out what the console output would look like, and then validate there's no leading whitespace on the SDK version number list.

PR Checklist

• Meaningful title, helpful description and a linked NuGet/Home issue
• Added tests see description
• Link to an issue or pull request to update docs if this PR changes settings, environment variables, new feature, etc: Revise .NET 10 SDK known issues and workarounds dotnet/core#10201