* fix: Proxy closing listener with 0 connections left
A bug was introduced in `0.15.0` where sessions with max connection counts were closed when the connections left hit 0. This issue was highlighted by a user: https://github.com/hashicorp/boundary/issues/4364. What was happening was when we have zero connections left the proxy code was closing the listener which closed its connections
To fix this:
- `boundary connect -target-id=xx -host-id=xx` command with no connections left will now wait for all connections to be closed and before exiting the session just like it did in `0.14.3`
- As soon as there are no more connections left, the listener will close to stop accepting new connections
- Fix issue where the websocket connection was throwing closing errors during the session teardown.
Elim Tsiagbey
1b1c8b3bf9