[roll] Roll fuchsia [analytics][fx][build] Improved target_count

- Added and modified python script from Aaron to count ninja actions
  more accurately
- Added metrics_version user property to distinguish old target_count
  with new target_count

Original-Fixed: b/410570041
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1259624
Original-Revision: 5b1d72076e80d67c496dcf45cbf814f0d6a059a1
GitOrigin-RevId: 79740d7463f16ad24924478ba80eb17e91d59484
Change-Id: I4e11e4a317af44a86d8e6bfb4e879dc401093c8e
diff --git a/stem b/stem
index a9f4799..7f05b67 100644
--- a/stem
+++ b/stem
@@ -8,7 +8,7 @@
              root=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="f76edd89aadec3f59f9ebd7ae5fdab18625e134f"
+             revision="5b1d72076e80d67c496dcf45cbf814f0d6a059a1"
              />
   </imports>
   <projects>