[roll] Roll fuchsia [superproject] Roll third_party/pigweed Revert "pw_bluetooth_proxy: Use std::lock_guard"

This reverts commit 54ca0db892863f6d278dc9ca5be92591d1b9f98b.

Reason for revert: Breaks downstream client

Original-Bug: 377889745

Original change's description:
> pw_bluetooth_proxy: Use std::lock_guard
>
> Now that std::lock_guard is available to downstream clients, stop
> manually locking/unlocking mutexes.
>
> Change-Id: I7104ccfd473791e9df0e935db03e8ea6aff67e9d
> Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/241192
> Reviewed-by: David Rees <[email protected]>
> Docs-Not-Needed: Austin Foxley <[email protected]>
> Commit-Queue: Auto-Submit <[email protected]>
> Pigweed-Auto-Submit: Austin Foxley <[email protected]>
> Lint: Lint 🤖 <[email protected]>

# Not skipping CQ checks because original CL landed > 1 day ago.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/247633
Original-Revision: b2288d8bc5b9098343d3d9b76c6b3f0d38ddb948
GitOrigin-RevId: 98c3e3c45e60c72c197301a8e7886c1fca419b1f
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1153252
Original-Revision: 81694492ff21f7bf600afbdaf306c21846517a39
Change-Id: I8861857ac0bf27b64da2b3f6b67717ebc4c3851e

Author: global-integration-roller

stem

@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="188b391518da48f508bb4b777d915d064fe499d6"/>
+             revision="81694492ff21f7bf600afbdaf306c21846517a39"/>
   </projects>
   <hooks>
     <hook name="install-environment"