🥅 Properly display error responses

lib/main.dart

@@ -111,6 +111,29 @@ class _GoMixHomeState extends State<GoMixHome> {
           }
         });
       }
+
+      if (data["type"] == "error") {
+        String errorMessage = "";
+        try {
+          errorMessage = data["responseData"]["error"];
+        } catch (e) {
+          errorMessage = "Unknown error";
+        }
+
+        showDialog<String>(
+          context: context,
+          builder: (BuildContext context) => AlertDialog(
+            title: const Text('Server error'),
+            content: Text(errorMessage),
+            actions: <Widget>[
+              TextButton(
+                onPressed: () => Navigator.pop(context, 'OK'),
+                child: const Text('OK'),
+              ),
+            ],
+          ),
+        );
+      }
     }, onDone: () {
       wsConnected = false;
       if (connectionError.value != "") return;