[IntentHandling] Remove FindWebTasks

This is no longer used after switching web tasks to FindAppServiceTasks

Bug: 1240018
Change-Id: I910115ee129326a5e9991d7af5f2ba01526a17db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3116584


Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Cr-Commit-Position: refs/heads/main@{#919124}