Fixed create merge request button not enabling

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64454

app/assets/javascripts/create_merge_request_dropdown.js

@@ -182,7 +182,7 @@ export default class CreateMergeRequestDropdown {
   }
 
   enable() {
-    if (!canCreateConfidentialMergeRequest()) return;
+    if (isConfidentialIssue() && !canCreateConfidentialMergeRequest()) return;
 
     this.createMergeRequestButton.classList.remove('disabled');
     this.createMergeRequestButton.removeAttribute('disabled');

spec/frontend/create_merge_request_dropdown_spec.js

 import axios from '~/lib/utils/axios_utils';
 import MockAdapter from 'axios-mock-adapter';
 import CreateMergeRequestDropdown from '~/create_merge_request_dropdown';
+import confidentialState from '~/confidential_merge_request/state';
 import { TEST_HOST } from './helpers/test_constants';
 
 describe('CreateMergeRequestDropdown', () => {
@@ -66,4 +67,37 @@ describe('CreateMergeRequestDropdown', () => {
       );
     });
   });
+
+  describe('enable', () => {
+    beforeEach(() => {
+      dropdown.createMergeRequestButton.classList.add('disabled');
+    });
+
+    afterEach(() => {
+      confidentialState.selectedProject = {};
+    });
+
+    it('enables button when not confidential issue', () => {
+      dropdown.enable();
+
+      expect(dropdown.createMergeRequestButton.classList).not.toContain('disabled');
+    });
+
+    it('enables when can create confidential issue', () => {
+      document.querySelector('.js-create-mr').setAttribute('data-is-confidential', 'true');
+      confidentialState.selectedProject = { name: 'test' };
+
+      dropdown.enable();
+
+      expect(dropdown.createMergeRequestButton.classList).not.toContain('disabled');
+    });
+
+    it('does not enable when can not create confidential issue', () => {
+      document.querySelector('.js-create-mr').setAttribute('data-is-confidential', 'true');
+
+      dropdown.enable();
+
+      expect(dropdown.createMergeRequestButton.classList).toContain('disabled');
+    });
+  });
 });