[declutter] Add declutter dialog coordinator/view

Bug: 340581912
Change-Id: I0e7fd8e403e3645521a1866c7c9cbf5dc1295d53
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5605411


Commit-Queue: Brandon Wylie <wylieb@google.com>
Reviewed-by: Calder Kitagawa <ckitagawa@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1312156}