[Files app] Prefer AbortController over EventTracker

The EventTracker is a WebUI class the allows for mass removal of event
listeners all at once. This functionality has available in the
AbortController which is a native Web API. Currently there are some
interesting type hacks to enable its usage, which are not required when
using the AbortController.

Fixed: b/255484929
Change-Id: Ia07dd764071c7c8837ed35d53e79fd37fe591483
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5138021
Commit-Queue: Ben Reich <benreich@chromium.org>
Reviewed-by: Wenbo Jie <wenbojie@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1239553}