Fixed Ember Data deprecation warnings for `queryRecord` response returning array

no issue

- our API always returns an array whether we're performing a browse or find request but Ember Data expects explicit find requests to return a single object and throws deprecations when it sees an array
  - https://deprecations.emberjs.com/ember-data/v2.x/#toc_store-queryrecord-array-response-with-restserializer
- we previously had `normalizeSingleResponse` overrides in specific models that we use with `queryRecord` but we've since introduced `queryRecord` usage on more models but the associated "fix" was not duplicated in the serializers for those models leading to many deprecation warnings logged to the console in development and when testing
- moved the fix to the application serializer so it applies to all models
  - explicitly excluded `setting` model because that's a special-case and has it's own array-into-object serialization to represent multiple settings records as a single model instance

app/serializers/application.js

@@ -49,4 +49,16 @@ export default class Application extends RESTSerializer {
 
         return transform(key);
     }
+
+    normalizeQueryRecordResponse(store, primaryModelClass, payload) {
+        const root = this.keyForAttribute(primaryModelClass.modelName);
+        const pluralizedRoot = pluralize(root);
+
+        if (payload[pluralizedRoot] && root !== 'setting') {
+            payload[root] = payload[pluralizedRoot][0];
+            delete payload[pluralizedRoot];
+        }
+
+        return super.normalizeQueryRecordResponse(...arguments);
+    }
 }

app/serializers/post.js

@@ -1,7 +1,6 @@
 /* eslint-disable camelcase */
 import ApplicationSerializer from 'ghost-admin/serializers/application';
 import {EmbeddedRecordsMixin} from '@ember-data/serializer/rest';
-import {pluralize} from 'ember-inflector';
 
 export default class PostSerializer extends ApplicationSerializer.extend(EmbeddedRecordsMixin) {
     // settings for the EmbeddedRecordsMixin.
@@ -14,22 +13,6 @@ export default class PostSerializer extends ApplicationSerializer.extend(Embedde
         email: {embedded: 'always'}
     };
 
-    normalizeSingleResponse(store, primaryModelClass, payload) {
-        let root = this.keyForAttribute(primaryModelClass.modelName);
-        let pluralizedRoot = pluralize(primaryModelClass.modelName);
-
-        if (payload[pluralizedRoot]) {
-            payload[root] = payload[pluralizedRoot][0];
-            delete payload[pluralizedRoot];
-        }
-
-        return super.normalizeSingleResponse(...arguments);
-    }
-
-    normalizeArrayResponse() {
-        return super.normalizeArrayResponse(...arguments);
-    }
-
     serialize(/*snapshot, options*/) {
         let json = super.serialize(...arguments);
 

app/serializers/user.js

@@ -19,16 +19,4 @@ export default class UserSerializer extends ApplicationSerializer.extend(Embedde
 
         return super.extractSingle(...arguments);
     }
-
-    normalizeSingleResponse(store, primaryModelClass, payload) {
-        let root = this.keyForAttribute(primaryModelClass.modelName);
-        let pluralizedRoot = pluralize(primaryModelClass.modelName);
-
-        if (payload[pluralizedRoot]) {
-            payload[root] = payload[pluralizedRoot][0];
-            delete payload[pluralizedRoot];
-        }
-
-        return super.normalizeSingleResponse(...arguments);
-    }
 }