webrtc-api example: do not rely on webpack / npm proxying websocket

Instead simply use the desired address directly from the reference
example, this makes it work out of the box without placing expectations
on the web server.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1674>

net/webrtc/gstwebrtc-api/index.html

@@ -419,7 +419,7 @@
       const signalingProtocol = window.location.protocol.startsWith("https") ? "wss" : "ws";
       const gstWebRTCConfig = {
         meta: { name: `WebClient-${Date.now()}` },
-        signalingServerUrl: `${signalingProtocol}://${window.location.host}/webrtc`,
+        signalingServerUrl: `${signalingProtocol}://${window.location.hostname}:8443`,
       };
 
       const api = new GstWebRTCAPI(gstWebRTCConfig);

net/webrtc/gstwebrtc-api/webpack.config.cjs

@@ -20,12 +20,6 @@ const config = {
   devServer: {
     open: true,
     static: false,
-    proxy: {
-      "/webrtc": {
-        target: "ws://127.0.0.1:8443",
-        ws: true
-      }
-    },
     server: "https",
     port: 9090
   },