status/network: Sync active access point from constructor

The wireless device item tracks the active access point in order
to update its icon on signal strength changes.

However we currently don't synchronize the initial state, so we
miss strength changes until the first access-point change.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2406>

js/ui/status/network.js

@@ -1273,6 +1273,7 @@ var NMDeviceWireless = class extends Signals.EventEmitter {
             'notify::active-access-point', this._activeApChanged.bind(this),
             'state-changed', this._deviceStateChanged.bind(this), this);
 
+        this._activeApChanged();
         this._sync();
     }