fix: ensure wsproxy `MultiAgent` is closed when websocket dies#11414

coadler merged 4 commits intomaincoder/coder:mainfrom

colin/fixensurewsproxyMultiAgentisclosedwhenwebsocketdiescoder/coder:colin/fixensurewsproxyMultiAgentisclosedwhenwebsocketdiesCopy head branch name to clipboard