[roll] Roll fuchsia [ffx] Combine target_holders and daemon_proxy

ffx_daemon_proxy is on the critical path because target_holders
depends on it. But it is only one file, and target_holders is the
only crate that depends on it. By removing the crate, we can speed
up the build-time.

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1281748
Original-Revision: 534895e40f0230ad2c5f6320aef7022338a7bdd1
GitOrigin-RevId: 01a54475a0fda156753a13cc99ec5748c321b9d1
Change-Id: I3bd0488fa59ac9f266f911883eab6d9efe8db872
diff --git a/stem b/stem
index e95957e..bddda28 100644
--- a/stem
+++ b/stem
@@ -7,7 +7,7 @@
             manifest="manifests/platform"
             root=""
             remote="https://fuchsia.googlesource.com/fuchsia"
-            revision="d8dab31a6204716d8f960f6eca1601476f8df1d2"/>
+            revision="534895e40f0230ad2c5f6320aef7022338a7bdd1"/>
   </imports>
   <projects>
     <project name="cobalt"