Improve async/await usage, and sort init calls in index.js (#17386)

* clean up async/await, and sort init calls in `index.js
* use `const _promise` to indicate that we do not need await an async function

web_src/js/features/comp/WebHookEditor.js

@@ -1,6 +1,6 @@
 const {csrfToken} = window.config;
 
-export function initWebHookEditor() {
+export function initCompWebHookEditor() {
   if ($('.new.webhook').length === 0) {
     return;
   }