Migrate dropdown to gl-dropdown for fuzzing artifacts

* Udpate unit tests

ee/app/assets/javascripts/security_dashboard/components/fuzzing_artifacts_download.vue

 <script>
-import { GlButton, GlDropdown, GlDeprecatedDropdownItem } from '@gitlab/ui';
+import { GlButton, GlDropdown, GlDropdownItem } from '@gitlab/ui';
 import { s__ } from '~/locale';
 
 export default {
@@ -9,7 +9,7 @@ export default {
   components: {
     GlButton,
     GlDropdown,
-    GlDeprecatedDropdownItem,
+    GlDropdownItem,
   },
   props: {
     jobs: {
@@ -46,12 +46,9 @@ export default {
       category="secondary"
       size="small"
     >
-      <gl-deprecated-dropdown-item
-        v-for="job in jobs"
-        :key="job.id"
-        :href="artifactDownloadUrl(job)"
-        >{{ job.name }}</gl-deprecated-dropdown-item
-      >
+      <gl-dropdown-item v-for="job in jobs" :key="job.id" :href="artifactDownloadUrl(job)">{{
+        job.name
+      }}</gl-dropdown-item>
     </gl-dropdown>
     <gl-button
       v-else

ee/spec/frontend/security_dashboard/components/fuzzing_artifacts_download_spec.js

-import { GlButton, GlDropdown, GlDeprecatedDropdownItem } from '@gitlab/ui';
+import { GlButton, GlDropdown, GlDropdownItem } from '@gitlab/ui';
 import { shallowMount, createLocalVue } from '@vue/test-utils';
 import Vuex from 'vuex';
 import FuzzingArtifactsDownload from 'ee/security_dashboard/components/fuzzing_artifacts_download.vue';
@@ -60,11 +60,11 @@ describe('Filter component', () => {
     it('should render a dropdown button with several items', () => {
       expect(wrapper.find(GlButton).exists()).toBe(false);
       expect(wrapper.find(GlDropdown).exists()).toBe(true);
-      expect(wrapper.findAll(GlDeprecatedDropdownItem).length).toBe(2);
+      expect(wrapper.findAll(GlDropdownItem).length).toBe(2);
     });
 
     it('should render with href set to the correct filepath for every element', () => {
-      const wrapperArray = wrapper.findAll(GlDeprecatedDropdownItem);
+      const wrapperArray = wrapper.findAll(GlDropdownItem);
       wrapperArray.wrappers.forEach((_, index) => {
         const href = `/api/v4/projects/${projectId}/jobs/artifacts/${
           jobs[index].ref