Remove Lacros support from feedback tools, part 3

This CL primarily removes Lacros log fetching from
ash's FeedbackService.

Bug: b:365741912
Change-Id: I943fbb8da2cb12c6dd4f14154a32d4edb1ad6db8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5898284
Reviewed-by: Xiangdong Kong <xiangdongkong@google.com>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Emilia Paz <emiliapaz@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1362830}
NOKEYCHECK=True
GitOrigin-RevId: 75c7193f81050818393c215d714c9f45cf7a3f18