[roll] Roll fuchsia [ffx][repository] add-from-pm stops overwriting existing repos

Previously, `ffx repository add-from-pm` would silently overwrite
repositories when adding a second one under the same name. Now, it will
error out if an already known repo is to be added, informing the user.

Original-Fixed: b/300158417
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1047892
Original-Revision: 307205e717eb4965cc2bcb675d6d35898e9d7b95
GitOrigin-RevId: ae458c325254646d0855d6bd4cc84d54af6f0f3c
Change-Id: Idba92f70273214f16a5db1ddd0cf7fec72a8ffac
diff --git a/stem b/stem
index 3922d39..e087da9 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="36c3d81d7c31fd20a73e57d1957858edd6cb1be7"/>
+             revision="307205e717eb4965cc2bcb675d6d35898e9d7b95"/>
   </projects>
   <hooks>
     <hook name="install-environment"