[server, relay] Fix/relay race disconnection (#4174)

Avoid invalid disconnection notifications in case the closed race dials.
In this PR resolve multiple race condition questions. Easier to understand the fix based on commit by commit.

- Remove store dependency from notifier
- Enforce the notification orders
- Fix invalid disconnection notification
- Ensure the order of the events on the consumer side

relay/client/client.go

@@ -292,7 +292,7 @@ func (c *Client) Close() error {
 }
 
 func (c *Client) connect(ctx context.Context) (*RelayAddr, error) {
-	rd := dialer.NewRaceDial(c.log, c.connectionURL, quic.Dialer{}, ws.Dialer{})
+	rd := dialer.NewRaceDial(c.log, dialer.DefaultConnectionTimeout, c.connectionURL, quic.Dialer{}, ws.Dialer{})
 	conn, err := rd.Dial()
 	if err != nil {
 		return nil, err