Dropped use of `@classic` decorator in transforms

refs https://github.com/TryGhost/Admin/pull/2242

- there was no further EmberObject specific usage to migrate for these classes so the @classic decorator is not necessary

app/transforms/facebook-url-user.js

@@ -1,7 +1,5 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 
-@classic
 export default class FacebookUrlUser extends Transform {
     deserialize(serialized) {
         if (serialized) {

app/transforms/json-string.js

@@ -1,7 +1,5 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 
-@classic
 export default class JsonString extends Transform {
     deserialize(serialized) {
         let _serialized = serialized === '' ? null : serialized;

app/transforms/member-product.js

@@ -1,9 +1,7 @@
 import MemberProduct from 'ghost-admin/models/member-product';
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import {A as emberA, isArray as isEmberArray} from '@ember/array';
 
-@classic
 export default class MemberProductTransform extends Transform {
     deserialize(serialized) {
         let subscriptions, subscriptionArray;

app/transforms/member-subscription.js

@@ -1,9 +1,7 @@
 import MemberSubscription from 'ghost-admin/models/member-subscription';
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import {A as emberA, isArray as isEmberArray} from '@ember/array';
 
-@classic
 export default class MemberSubscriptionTransform extends Transform {
     deserialize(serialized) {
         let subscriptions, subscriptionArray;

app/transforms/moment-date.js

@@ -1,8 +1,6 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import moment from 'moment';
 
-@classic
 export default class MomentDate extends Transform {
     deserialize(serialized) {
         if (serialized) {

app/transforms/moment-utc.js

@@ -1,8 +1,6 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import moment from 'moment';
 
-@classic
 export default class MomentUtc extends Transform {
     deserialize(serialized) {
         if (serialized) {

app/transforms/navigation-settings.js

@@ -1,9 +1,7 @@
 import NavigationItem from 'ghost-admin/models/navigation-item';
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import {A as emberA, isArray as isEmberArray} from '@ember/array';
 
-@classic
 export default class NavigationSettings extends Transform {
     deserialize(serialized, options) {
         let navItems, settingsArray;
@@ -27,8 +25,8 @@ export default class NavigationSettings extends Transform {
 
         if (isEmberArray(deserialized)) {
             settingsArray = deserialized.map((item) => {
-                let label = item.get('label').trim();
-                let url = item.get('url').trim();
+                let label = item.label.trim();
+                let url = item.url.trim();
 
                 return {label, url};
             }).compact();

app/transforms/product-benefits.js

@@ -1,9 +1,7 @@
 import ProductBenefitItem from '../models/product-benefit-item';
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import {A as emberA, isArray as isEmberArray} from '@ember/array';
 
-@classic
 export default class ProductBenefits extends Transform {
     deserialize(serialized) {
         let benefitsItems, benefitsArray;

app/transforms/raw.js

@@ -1,7 +1,5 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 
-@classic
 export default class Raw extends Transform {
     deserialize(serialized) {
         return serialized;

app/transforms/slack-settings.js

@@ -1,11 +1,9 @@
-import classic from 'ember-classic-decorator';
 /* eslint-disable camelcase */
 import SlackObject from 'ghost-admin/models/slack-integration';
 import Transform from '@ember-data/serializer/transform';
 import {isArray as isEmberArray} from '@ember/array';
 import {isEmpty} from '@ember/utils';
 
-@classic
 export default class SlackSettings extends Transform {
     deserialize(serialized) {
         let settingsArray;

app/transforms/stripe-price.js

@@ -1,9 +1,7 @@
 import StripePrice from 'ghost-admin/models/stripe-price';
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 import {A as emberA, isArray as isEmberArray} from '@ember/array';
 
-@classic
 export default class StripePriceTransform extends Transform {
     deserialize(serialized) {
         if (serialized === null || serialized === undefined) {

app/transforms/twitter-url-user.js

@@ -1,7 +1,5 @@
 import Transform from '@ember-data/serializer/transform';
-import classic from 'ember-classic-decorator';
 
-@classic
 export default class TwitterUrlUser extends Transform {
     deserialize(serialized) {
         if (serialized) {