Revert addition of shell.Stop() to ExecuteCommandAsync()

This unintentionally introduced a bug with the PSReadLine integration
which left users needing to press `ENTER` in the console to start or
continue the debugger.

Author: andyleejordan

src/PowerShellEditorServices/Services/PowerShellContext/PowerShellContextService.cs

@@ -765,7 +765,6 @@ public async Task<IEnumerable<TResult>> ExecuteCommandAsync<TResult>(
                     }
 
                     // This is the primary reason that ExecuteCommandAsync takes a CancellationToken
-                    cancellationToken.Register(() => shell.Stop());
                     return await Task.Run<IEnumerable<TResult>>(
                         () => shell.Invoke<TResult>(input: null, invocationSettings), cancellationToken)
                         .ConfigureAwait(false);