[roll] Roll fuchsia [virtualization] Move stateful partition size to structured config

This just moves the partition size from a constant into structured
configuration. This makes the value easier to modify and also allows
tests to augment this value.

Original-Bug: 107399
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/714872
Original-Revision: 74cbdf3bd26729d88603f6076f10f61a289b1dcf
GitOrigin-RevId: 45b72bf9ac6a279a6c8777549fdda93cdc4c46d2
Change-Id: I88851cadc5bcfa41da6861df40cd6a2250b523be

stem

diff --git a/stem b/stem
index 0b5154c..aa8b8de 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="cc8d451d3031b7297bee97068286998aa73db7cd"/>
+             revision="74cbdf3bd26729d88603f6076f10f61a289b1dcf"/>
   </projects>
   <hooks>
     <hook name="install-environment"