[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: 035db15fd92b65f12bfeeebf4ca906dc5c8e5958
Roller-URL: https://cr-buildbucket.appspot.com/build/8731902490844456977
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I8d1ac4270917927033603c53bd06ca1ac41b6bf9
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1153252

Author: global-integration-roller