Fix: linux: getSystemDevices (#154)

Make sure getSystemDevices connects the bluez client first.
This ensures that the list of devices is correctly populated.

Signed-off-by: Tim Froidcoeur <tim.froidcoeur@comate.be>
Co-authored-by: Tim Froidcoeur <tim.froidcoeur@comate.be>

lib/src/universal_ble_linux/universal_ble_linux.dart

@@ -350,6 +350,7 @@ class UniversalBleLinux extends UniversalBlePlatform {
   Future<List<BleDevice>> getSystemDevices(
     List<String>? withServices,
   ) async {
+    await _ensureInitialized();
     List<BlueZDevice> devices =
         _client.devices.where((device) => device.connected).toList();
     if (withServices != null && withServices.isNotEmpty) {