Remove manual jquery mocking

- Uses old assertion before jest migration

spec/frontend/blob/blob_file_dropzone_spec.js

@@ -5,10 +5,6 @@ describe('BlobFileDropzone', () => {
   preloadFixtures('blob/show.html');
   let dropzone;
   let replaceFileButton;
-  const jQueryMock = {
-    enable: jest.fn(),
-    disable: jest.fn(),
-  };
 
   beforeEach(() => {
     loadFixtures('blob/show.html');
@@ -18,7 +14,6 @@ describe('BlobFileDropzone', () => {
     dropzone = $('.js-upload-blob-form .dropzone').get(0).dropzone;
     dropzone.processQueue = jest.fn();
     replaceFileButton = $('#submit-all');
-    $.fn.extend(jQueryMock);
   });
 
   describe('submit button', () => {
@@ -43,7 +38,7 @@ describe('BlobFileDropzone', () => {
       replaceFileButton.click();
 
       expect(window.alert).not.toHaveBeenCalled();
-      expect(jQueryMock.enable).toHaveBeenCalled();
+      expect(replaceFileButton.is(':disabled')).toEqual(true);
       expect(dropzone.processQueue).toHaveBeenCalled();
     });
   });

spec/frontend/boards/board_new_issue_spec.js

 /* global List */
 
-import $ from 'jquery';
 import Vue from 'vue';
 import MockAdapter from 'axios-mock-adapter';
 import axios from '~/lib/utils/axios_utils';
@@ -15,9 +14,6 @@ describe('Issue boards new issue form', () => {
   let list;
   let mock;
   let newIssueMock;
-  const jQueryMock = {
-    enable: jest.fn(),
-  };
   const promiseReturn = {
     data: {
       iid: 100,
@@ -53,8 +49,6 @@ describe('Issue boards new issue form', () => {
       },
     }).$mount(document.querySelector('.test-container'));
 
-    $.fn.extend(jQueryMock);
-
     return Vue.nextTick();
   });
 
@@ -118,7 +112,7 @@ describe('Issue boards new issue form', () => {
       return Vue.nextTick()
         .then(submitIssue)
         .then(() => {
-          expect(jQueryMock.enable).toHaveBeenCalled();
+          expect(vm.$el.querySelector('.btn-success').disabled).toBe(false);
         });
     });