Use explicit jQuery import, remove unused eslint globals (#18435)

- Don't rely on globals (window.$) for jQuery import
- Remove eslint globals no longer in use

web_src/js/features/repo-issue-content.js

@@ -1,7 +1,7 @@
+import $ from 'jquery';
 import {svg} from '../svg.js';
 
 const {appSubUrl, csrfToken} = window.config;
-
 let i18nTextEdited;
 let i18nTextOptions;
 let i18nTextDeleteFromHistory;