peer: make PingManager disconnect call async

In this commit, we make all calls to disconnect after a ping/pong
violation is detected in the `PingManager` async. We do this to avoid
circular waiting that may occur if the disconnect call back ends up
waiting on the peer goroutine to be torn down. If this happens, then the
peer goroutine will be blocked on the ping manager fully tearing down,
which is blocked on the peer disconnect succeeding.

This is a similar class of issue we've delt with recently as pertains to
the peer and the server: sync all back execution must not lead to
a circular waiting loop.

Fixes #8379

peer/brontide.go

@@ -577,7 +577,7 @@ func NewBrontide(cfg Config) *Brontide {
 			eStr := "pong response failure for %s: %v " +
 				"-- disconnecting"
 			p.log.Warnf(eStr, p, err)
-			p.Disconnect(fmt.Errorf(eStr, p, err))
+			go p.Disconnect(fmt.Errorf(eStr, p, err))
 		},
 	})