Bump external/usersim from `d91240e` to `b3d70f2`

Bumps [external/usersim](https://github.com/microsoft/usersim) from `d91240e` to `b3d70f2`.
- [Commits](d91240e391...b3d70f2e4e)

---
updated-dependencies:
- dependency-name: external/usersim
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

external/usersim

@@ -1 +1 @@
-Subproject commit d91240e391a5a966fd7b4090b4e1b64a4deb856d
+Subproject commit b3d70f2e4e42034e4bacbc7a9d86c9145749bc6f