Updated port discovery to support unknown boards

From now on, we do not retrieve the ports from the attached boards.
A board can be unknown but the port is still relevant.

Signed-off-by: Akos Kitta <kittaakos@typefox.io>

arduino-ide-extension/src/browser/monitor/monitor-widget.tsx

@@ -268,7 +268,7 @@ export class MonitorWidget extends ReactWidget implements StatefulWidget {
         return {
             baudRate,
             board: selectedBoard,
-            port: selectedPort
+            port: selectedPort.address
         }
     }