ConnectionService: Fix duplicate callbacks.

app/src/main/java/de/ccc/events/badge/card10/common/ConnectionService.kt

@@ -65,6 +65,11 @@ object ConnectionService {
     }
 
     fun connect(context: Context) {
+        if (isConnected()) {
+            gattListeners.values.map { it.onConnectionReady() }
+            return
+        }
+
         // Use first BLE devices that is bonded
         val bondedDevices = BluetoothAdapter.getDefaultAdapter().bondedDevices.filter {
             it.address.startsWith(