Refactor test cases for USB flow and port labels for improved readability

test/screens/usb_flow_test.dart

@@ -172,18 +172,13 @@ void main() {
       );
       await tester.pumpAndSettle();
 
-      expect(
+      expect(find.text('USB permission was denied.'), findsOneWidget);
-        find.text('USB permission was denied.'),
-        findsOneWidget,
-      );
     });
 
-    testWidgets(
+    testWidgets('connection failure completes without leaving loading state', (
-      'connection failure completes without leaving loading state',
+      tester,
-      (tester) async {
+    ) async {
-      final connector = _FakeMeshCoreConnector(
+      final connector = _FakeMeshCoreConnector(ports: <String>['COM1']);
-        ports: <String>['COM1'],
-      );
       var connectAttempted = false;
       connector.connectUsbImpl = ({required String portName}) async {
         connectAttempted = true;

test/utils/usb_port_labels_test.dart

@@ -46,9 +46,7 @@ void main() {
 
   test('friendlyUsbPortName trims whitespace from label parts', () {
     expect(
-      friendlyUsbPortName(
+      friendlyUsbPortName(' /dev/ttyS0  -  My Serial Port   -  n/a '),
-        ' /dev/ttyS0  -  My Serial Port   -  n/a ',
-      ),
       'My Serial Port',
     );
   });