Allow client to not sleep/disconnect while in forced passthrough

Currently, when you leave boundaries, or enable passthrough, it will disconnect (and sleep) alvr.
This is slightly inconvenient when you just want to reach out for something for a second, and/or sometimes you may still want to talk with someone while you're out of boundaries, in passthrough mode.
It would be nice to have toggle for this:
1. False - Disconnect client on boundaries leave or forced passthrough (default behavior in current alvr)
2. True - Don't disconnect or sleep client and allow for tracking/mic/everything as usual when you leave boundaries or enable passthrough.

This would be similar to how currently ALXR works.
I also noticed that on ALXR it sort of throttles tracking while in that mode (lower hz), but it may be runtime-specific (not that important if it still works)