fix(daemon/server): break out of the stream-events handler

[Profpatsch]

If the client disengages, we need to stop the handler immediately, otherwise we keep it running in the for-loop for all times.

This fixes a problem where any call of the lorri internal stream-events --kind snapshot client would drop the connection, and the handler would trace it but not stop itself.

Fixes https://github.com/nix-community/lorri/issues/35

• [ ] Amended the changelog in release.nix (see release.nix for instructions)

[Profpatsch]

cc @symphorien