[roll] Roll fuchsia [bt-opp-client] Add empty test target to build graph

This should catch breaking changes to bt-opp-client.

Test: fx build
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1109760
Original-Revision: 285364bc24fa70b456293888110577464d3f70a7
GitOrigin-RevId: 858f2fe73acfb84c8c669a6c02d334299fdcceb4
Change-Id: I9aac21331b0143e0edbd1b337d179f9beea356e9
diff --git a/stem b/stem
index 5414342..8c9473f 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="a62432d2f1980b586becca34c78d048004789ee9"/>
+             revision="285364bc24fa70b456293888110577464d3f70a7"/>
   </projects>
   <hooks>
     <hook name="install-environment"