Ingest changes from NuGet that allow for modal dialogs to be launched

[baronfel]

This is the tracking issue for NuGet/Home#14010 because GitHub subissues can't be linked across repositories or organizations.

SDK is on-board with NuGet changing canShowDialog, and so this tracks merging the fix from their end once it is made.

Major changes in user experience are:

current state

Tokens can be long-lived based on org configurations. 7 or 30 days is not uncommon. These long-lived tokens are exchanged for short-lived tokens transparently. The authentication flow is the device code flow.

When a user interactively authenticates today, a message is printed to the console directing a user to navigate to a specific url, where they can authenticate, which unblocks the build.

proposed new state

Long-lived tokens will have a day lifespan. These tokens are exchanged for short-lived tokens transparently.

When a user interactively authenticates today, a browser will open automatically that the user can authenticate through. A message is printed to the build alerting the user to this. Once the authentication flow is completed the build is unblocked.

Key validation points

After this change, builds through msbuild.exe, dotnet msbuild and dotnet build should still

• fail authentication if unauthenticated and --interactive is not passed
• trigger the authentication flow with a console message + browser popup if --interactive is allowed.