[scoped-vt] Invoke DOM callbacks in creation order

Bug: 456739886

Change-Id: I17ee8da5b777297cc3cdc699869ae8a6135fb845
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7101482
Reviewed-by: Vladimir Levin <vmpstr@chromium.org>
Commit-Queue: Kevin Ellis <kevers@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1539505}

Author: kevers-google

css/css-view-transitions/scoped/callback-order.tentative.html

@@ -9,10 +9,15 @@
 </head>
 <style>
   #target {
+    position: relative;
     background-color: blue;
     height: 100px;
     width: 100px;
-    z-index: 1;
+    contain: view-transition;
+    view-transition-name: none;
+  }
+  #child {
+    position: relative;
   }
 </style>
 <script src="/resources/testharness.js"></script>