Move merge request artifact download

* Move component
* Move unit test
* Update imports/usages

ee/app/assets/javascripts/vue_shared/security_reports/grouped_security_reports_app.vue

@@ -11,7 +11,7 @@ import SummaryRow from '~/reports/components/summary_row.vue';
 import { LOADING } from '~/reports/constants';
 import Tracking from '~/tracking';
 import SecuritySummary from '~/vue_shared/security_reports/components/security_summary.vue';
-import MrArtifactDownload from './components/artifact_downloads/merge_request_artifact_download.vue';
+import MrArtifactDownload from '~/vue_shared/security_reports/components/artifact_downloads/merge_request_artifact_download.vue';
 import DastModal from './components/dast_modal.vue';
 import IssueModal from './components/modal.vue';
 import { securityReportTypeEnumToReportType } from './constants';

ee/spec/frontend/vue_shared/security_reports/components/artifact_downloads/mr_artifact_download_spec.js → spec/frontend/vue_shared/components/security_reports/artifact_downloads/mr_artifact_download_spec.js

 import { shallowMount } from '@vue/test-utils';
 import Vue from 'vue';
 import VueApollo from 'vue-apollo';
-import Component from 'ee/vue_shared/security_reports/components/artifact_downloads/merge_request_artifact_download.vue';
+import Component from 'vue_shared/security_reports/components/artifact_downloads/merge_request_artifact_download.vue';
 import {
   REPORT_TYPE_SAST,
   REPORT_TYPE_SECRET_DETECTION,
-} from 'ee/vue_shared/security_reports/constants';
+} from 'vue_shared/security_reports/constants';
 import createMockApollo from 'helpers/mock_apollo_helper';
 import {
   expectedDownloadDropdownProps,