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>

overlay-amd64-host/prebuilt.conf

diff --git a/overlay-amd64-host/prebuilt.conf b/overlay-amd64-host/prebuilt.conf
index ee15f84..6f3482e 100644
--- a/overlay-amd64-host/prebuilt.conf
+++ b/overlay-amd64-host/prebuilt.conf
@@ -1,2 +1,2 @@
 
-FULL_BINHOST="gs://cos-prebuilt/117/17730.609.0/sdk"
+FULL_BINHOST="gs://cos-prebuilt/117/18594.0.0/sdk"