test: Add missing account serializer test

Delete account password attribute in mirage to mimic API exactly

addons/api/tests/unit/models/account-test.js

@@ -4,21 +4,10 @@ import { setupTest } from 'ember-qunit';
 module('Unit | Model | account', function(hooks) {
   setupTest(hooks);
 
-  // Replace this with your real tests.
   test('it exists', function(assert) {
     let store = this.owner.lookup('service:store');
     let model = store.createRecord('account', {});
     assert.ok(model);
   });
 
-  test('it contains attributes', function(assert) {
-    let store = this.owner.lookup('service:store');
-    let model = store.createRecord('account', {
-      type: 'password',
-      attributes: {
-        login_name: 'loginname'
-      }
-    });
-    assert.equal(model.attributes.login_name, 'loginname');
-  });
 });