Update SDK to 18594.0.0

BUG=b/347026719
TEST=presubmit
RELEASE_NOTE=None

Change-Id: I77c4208b688b6cddddc479881119ba459d202694
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/77999
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>