fix: Preserve session_runner when restarting game session (fishfolk#971)

For map transitions, a session command restarting game session will be
used after updating map. This updates jumpy for related changes in:
fishfolk/bones#384

We can restart a networked game session by calling restart on session
runner, which handles existing socket + match id increment, implemented
on the bones side.

CI will fail until bones PR is merged + bones updated in lockfile.