Inspector: Stringify remote property values

This prevents us from asserting if the remote sends us a property made
up of an array or object.

DevTools/Inspector/RemoteObjectPropertyModel.cpp

@@ -56,7 +56,7 @@ GUI::Variant RemoteObjectPropertyModel::data(const GUI::ModelIndex& index, Role
         case Column::Name:
             return property.name;
         case Column::Value:
-            return property.value;
+            return property.value.to_string();
         }
     }
     return {};