[Ash] Delete Lacros influence in saved desk feature code

This CL deletes all Lacros leftovers and influences in the saved desk
feature code.

A potential next CL will be based on this CL, but to move it further, to
delete the entire desk profile feature code. As the desk profile feature
dependes on Lacros completely.

Bug: 354842935
Test: tryjob
Change-Id: Id63a2e07d736835789903d4f6a599d461a2084da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6289653
Commit-Queue: Di Wu <diwux@google.com>
Reviewed-by: Daniel Andersson <dandersson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1424184}