[ModConfig] Fix configuration save action

Since the `save()` function was changed to take in an argument, the save button action was sending the click event to the function which made it fail. Calling the function explicitly without an argument will fix it.

frontend/src/components/ModConfig.vue

@@ -460,7 +460,7 @@
       >
         Cancel
       </button>
-      <button @click="save">
+      <button @click="save()">
         <i>save</i>
         <span>Save</span>
       </button>