Add AutomatedPasswordChangeDetatchedWebContents to fieldtrial_testing_config

Change-Id: I8e42ae1a33b5a4ee08b01acc1ddb62011490ea93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7703799
Commit-Queue: Viktor Semeniuk <vsemeniuk@google.com>
Reviewed-by: Anna Tsvirchkova <atsvirchkova@google.com>
Cr-Commit-Position: refs/heads/main@{#1605398}
NOKEYCHECK=True
GitOrigin-RevId: 60f0a1157c2a8cb1778715c4181dfd160634dadf