Defterm commandline applications aren't under the WindowsTerminal process tree - maybe they should be?

[zadjii-msft]

1. set up defterm
2. run cmd.exe
3. see the following:

There's a OpenConsole -Embedding and a WindowsTerminal -Embedding that are started, but the cmd that is started is not parented to those - it's sitting as a child of explorer, and it still owns the system conhost that did the handoff.

We may need to somehow reparent the cmd.exe & it's conhost to the OpenConsole, or the WindowsTerminal - at least so they show up sanely in Task Manager.