Interactive window not started with active interpreter after changing active interpreters

[joyceerhl]

1. Pick an interpreter
2. Start the IW. IW gets started with the right interpreter
3. Switch interpreters
4. Close the IW
5. Reopen the IW
6. 🐛 IW doesn't get started with the new interpreter. Uses the originally selected interpreter instead.

[joyceerhl]

Root cause is we're caching the active interpreter controller at the notebookControllerManager level, and we never clear it out when the interpreter is changed. We're already caching the active interpreter at the pythonApi level and invalidating it when the interpreter changes, so I don't think caching the active interpreter controller in the notebookControllerManager buys us anything here.