fix(WebSocketPolyfill): run onopen callback on initialization

After a long offline period (>70 seconds), y-websocket's internal
watchdog closes the WebSocketPolyfill instance because no messages have
been received.

After going back online, y-websocket creates a new WebSocketPolyfill
instance to reconnect. In the new instance, syncService.open() is
called — but it returns early because the HTTP session is still alive.

This results in `wsconnected` staying false, which means that new steps
never get pushed to the server.

The fix is to run onopen callback explicitly in WebSocketPolyfill's
constructor.

Signed-off-by: Jonas <jonas@freesources.org>

Author: mejo-

src/services/WebSocketPolyfill.ts

@@ -66,6 +66,9 @@ export default function initWebSocketPolyfill(
 			syncService.bus.on('sync', this.#onSync)
 
 			syncService.open()
+			if (syncService.hasActiveConnection()) {
+				setTimeout(() => this.onopen?.(), 0)
+			}
 		}
 
 		/**