[LA Web] Add check for HTMLElement when looking for descendant with…

… animation. (#5749)

## Summary

This issue was found in
[Expensify](Expensify/App#37463).
`node.children` was undefined, because `node` wasn't `HTMLElement` - it
was `plaintext`. This PR introduces new check - if `node` is not
`HTMLElement`, we won't perform any action.

## Test plan

Tested on Expensify App

src/reanimated2/layoutReanimation/web/domUtils.ts

@@ -163,6 +163,12 @@ function findDescendantWithExitingAnimation(
   node: ReanimatedHTMLElement,
   root: Node
 ) {
+  // Node could be something else than HTMLElement, for example TextNode (treated as plain text, not as HTML object),
+  // therefore it won't have children prop and calling Array.from(node.children) will cause error.
+  if (!(node instanceof HTMLElement)) {
+    return;
+  }
+
   if (node.reanimatedDummy && node.removedAfterAnimation === undefined) {
     reattachElementToAncestor(node, root);
   }