[roll] Roll fuchsia [virtualization] Override structured config with RealmBuilder

Use realm builder to override structured configs instead of building
different packages with included configurations.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/720350
Original-Revision: 35320d74d9555bb860fdf62196ca6cf2b29c85e3
GitOrigin-RevId: d4d97d410f3b53c6289ecefcdcd7639029c9de5c
Change-Id: I6f604453d324b4dbcb5ebd6015e920c9e1fb12e8
diff --git a/stem b/stem
index 0bc74f8..c489980 100644
--- a/stem
+++ b/stem
@@ -10,7 +10,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="6e5eeea6cf31f4870616808c9019d2cca77a28e0"/>
+             revision="35320d74d9555bb860fdf62196ca6cf2b29c85e3"/>
   </projects>
   <hooks>
     <hook name="install-environment"