Optionally allow auto-accept for ensemble mode when no song is selected

[lilyvelour]

Is your feature request related to a problem? Please describe.
I currently play my bards directly from several midi devices, as opposed to midi files. I've noticed that I cannot auto-start ensemble mode with "Monitor Ensemble" checked, because it expects a song to be selected.

Describe the solution you'd like
Allow ensemble mode to start without a song selected if a midi input device is being listened to, or provide an option to enable this functionality.

Describe alternatives you've considered
At the moment, my workaround is to manually accept the ensemble ready check on all bards. This can be a headache as the number of bards grows.

Additional context
If this seems like too much work to implement, I'm happy to submit a PR! Would just need some guidance on how best to implement it.