Fix WebHookEditor regression from jQuery removal

Make these calls optional

Signed-off-by: Yarden Shoham <git@yardenshoham.com>

Author: yardenshoham

web_src/js/features/comp/WebHookEditor.js

@@ -23,12 +23,12 @@ export function initCompWebHookEditor() {
   }
 
   const updateContentType = function () {
-    const visible = document.getElementById('http_method').value === 'POST';
-    toggleElem(document.getElementById('content_type').parentNode.parentNode, visible);
+    const visible = document.getElementById('http_method')?.value === 'POST';
+    toggleElem(document.getElementById('content_type')?.parentNode.parentNode, visible);
   };
   updateContentType();
 
-  document.getElementById('http_method').addEventListener('change', updateContentType);
+  document.getElementById('http_method')?.addEventListener('change', updateContentType);
 
   // Test delivery
   document.getElementById('test-delivery')?.addEventListener('click', async function () {