[roll] Roll fuchsia [assembly] Specify images configs for bringup_fastboot

Use explicit images configs for bringup products instead of using the
global GN arguments.

We cannot assert that it is always provided yet, because we need to
add images config to internal boards.

Original-Bug: b/289074680
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/881592
Original-Revision: 324742b82df98de9c628c833caddc8a2ca11ee5d
GitOrigin-RevId: e48e49823f77d7f8658c5241e3b4b3420bdaae6a
Change-Id: Idaa7e532cf940f67b391f2cae3a92519e434d364
diff --git a/stem b/stem
index 15972ae..07fad8d 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="ed8c5e52b5e7177e6ff54d40a0ac4df943953428"/>
+             revision="324742b82df98de9c628c833caddc8a2ca11ee5d"/>
   </projects>
   <hooks>
     <hook name="install-environment"