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/comp/ReactionSelector.js

@@ -1,3 +1,4 @@
+import $ from 'jquery';
 const {csrfToken} = window.config;
 
 export function initCompReactionSelector(parent) {