Set 'There is no item to show' to all menu screens

lib/pages/TestPages/test_verify_screen.dart

@@ -230,7 +230,8 @@ class _TestVerifyScreenState extends State<TestVerifyScreen> {
                               color: Colors.black,
                             ),
                           )
-                        : ListView.builder(
+                        : testResults.items?.length != null ?
+                    ListView.builder(
                             controller: sc,
                             itemBuilder: (context, index) =>
                                 (testResults.items![index].verified == 'None' &&
@@ -246,7 +247,12 @@ class _TestVerifyScreenState extends State<TestVerifyScreen> {
                                     : Container(),
                             itemCount: testResults.items?.length,
                             shrinkWrap: true,
-                          );
+                          ) :
+                    Container(
+                      child: Center(
+                        child: Text("There is no item to show."),
+                      ),
+                    );
                   },
                 ),
               ),