Console output can be lost when cell execution is canceled

[jonsequitur]

The console output "Dispose" does not appear when the following code is canceled.

using System.Threading.Tasks;
using Microsoft.DotNet.Interactive;

Console.WriteLine("initialize");

var output = string.Empty.Display("text/plain");
var counter = 1;
while (!KernelInvocationContext.Current.CancellationToken.IsCancellationRequested)
{
    await Task.Delay(500);
    output.Update($"{counter++}");
}

Console.WriteLine("Dispose");

var completed = true;
``` 

This is because the `KernelInvocationContext` stops listening to console output and publishing events when it's completed. The behavior is unintuitive though and could perhaps be changed so that event publishing continues for long enough to capture this output.

More details here:
https://github.com/dotnet/interactive/issues/2987#issuecomment-2489136012