UX: Replace route when users try to access invalid group management page.

https://meta.discourse.org/t/unable-to-save-changes-to-a-group/84954

app/assets/javascripts/discourse/routes/group-manage-interaction.js.es6

@@ -0,0 +1,5 @@
+export default Discourse.Route.extend({
+  titleToken() {
+    return I18n.t('groups.manage.interaction.title');
+  },
+});

app/assets/javascripts/discourse/routes/group-manage-membership.js.es6

@@ -0,0 +1,11 @@
+export default Discourse.Route.extend({
+  titleToken() {
+    return I18n.t('groups.manage.membership.title');
+  },
+
+  afterModel(group) {
+    if (group.get('automatic')) {
+      this.replaceWith("group.manage.interaction", group);
+    }
+  },
+});

app/assets/javascripts/discourse/routes/group-manage-profile.js.es6

@@ -3,7 +3,9 @@ export default Discourse.Route.extend({
     return I18n.t('groups.manage.profile.title');
   },
 
-  model() {
-    return this.modelFor('group');
+  afterModel(group) {
+    if (group.get('automatic')) {
+      this.replaceWith("group.manage.interaction", group);
+    }
   },
 });