net.websocket: close the socket when the TLS connect in dial_socket fails (#28263)

`Client.dial_socket` dials the TcpConn and then runs `ws.ssl_conn.connect(mut t, …)!`, so a
failed TLS handshake propagates with the socket never closed — and since `ws.conn` is only
assigned after dial_socket returns, nothing downstream can close it either. Against a small
embedded TLS server every failed connect kept a half-open session on the peer until its own
timeout, and a few in a row exhausted its pool. Close it there, and the peer's half with it.

Author: MartenH

vlib/net/websocket/io.v

@@ -84,7 +84,12 @@ fn (mut ws Client) dial_socket() !&net.TcpConn {
 	t.set_read_timeout(ws.read_timeout)
 	t.set_write_timeout(ws.write_timeout)
 	if ws.is_ssl {
-		ws.ssl_conn.connect(mut t, ws.uri.hostname)!
+		ws.ssl_conn.connect(mut t, ws.uri.hostname) or {
+			// The TcpConn is not the client's yet, so nothing else can close it: a failed TLS
+			// handshake would otherwise leak the connected socket, and the peer's half of it.
+			t.close() or {}
+			return err
+		}
 	}
 	return t
 }