[observatory] Update Catapult to 3b3069e9b4a3220962b5bb1c21de02e35f4c2d84.

Bug: https://github.com/dart-lang/sdk/issues/34107
Bug: https://github.com/dart-lang/sdk/issues/40574
Bug: https://github.com/catapult-project/catapult/issues/2489
Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1036492
Change-Id: I129e47fbca902e3487e9deaf5b3a213b23dea2ef
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/135534
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/observatory/BUILD.gn

@@ -80,8 +80,6 @@ observatory_ignore_patterns = [
   "interop_support.*",
   "package.json",
   "unittest*",
-  "webcomponents-lite.js",
-  "webcomponents.*",
 ]
 
 if (!is_debug) {

runtime/observatory/web/timeline.html

@@ -4,6 +4,7 @@
   <meta charset="utf-8">
   <title>Dart VM Observatory Timeline</title>
   <script src="timeline_message_handler.js"></script>
+  <script src="third_party/webcomponents.min.js"></script>
   <link rel="import" href="third_party/trace_viewer_full.html">
   <script src="timeline.js"></script>
   <style>