depends: Update libmultiprocess library to fix CI failure

Bump libmultiprocess library to include bugfix
bitcoin-core/libmultiprocess#159 which should fix
intermittent CI failures reported in
bitcoin/bitcoin#31921

This change is bumping the libmultiprocess version instead of cherry picking
the bugfix. It could cherry-pick the bugfix instead, but there are reasons to
prefer bumping the version:

- Bugfix might interact with earlier PRs, and the latest version is better
  tested with testing done in many CI configurations in #30975 and #31802

- Even though we are in feature freeze for a release, the MULTIPROCESS=1 option
  is currently not enabled for release, so this PR only affect CI builds and
  local builds, not the release build.

This update brings in the following changes:

bitcoin-core/libmultiprocess#140 build: don't clobber user/superproject c++ version
bitcoin-core/libmultiprocess#142 build: add option for external mpgen binary
bitcoin-core/libmultiprocess#143 cleanup: initialize vars in the EventLoop constructor in the correct order
bitcoin-core/libmultiprocess#146 cmake: Suppress compiler warnings from capnproto headers
bitcoin-core/libmultiprocess#147 cmake: EXTERNAL_MPGEN cleanups
bitcoin-core/libmultiprocess#148 util: fix -Wpessimizing-move warning
bitcoin-core/libmultiprocess#145 CTest: Module must be included at the top level
bitcoin-core/libmultiprocess#149 Avoid `-Wundef` compiler warnings
bitcoin-core/libmultiprocess#152 refactor: Fix compiler and clang-tidy warnings
bitcoin-core/libmultiprocess#155 scripted-diff: s/Libmultiprocess_EXTERNAL_MPGEN/MPGEN_EXECUTABLE/g
bitcoin-core/libmultiprocess#156 refactor: Remove locale-dependent function calls
bitcoin-core/libmultiprocess#157 refactor: Avoid using std::format
bitcoin-core/libmultiprocess#159 bugfix: Do not lock EventLoop::mutex after EventLoop is done
bitcoin-core/libmultiprocess#161 cmake: Avoid including CTest if not top level project
bitcoin-core/libmultiprocess#164 Bump minimum required cmake to 3.12

Author: ryanofsky

depends/packages/native_libmultiprocess.mk

@@ -1,8 +1,8 @@
 package=native_libmultiprocess
-$(package)_version=07c917f7ca910d66abc6d3873162fc9061704074
+$(package)_version=1954f7f65661d49e700c344eae0fc8092decf975
 $(package)_download_path=https://github.com/chaincodelabs/libmultiprocess/archive
 $(package)_file_name=$($(package)_version).tar.gz
-$(package)_sha256_hash=ac9db311e3b22aac3c7b7b7b3f6b7fee5cf3043ebb3c3bf412049e8b17166de8
+$(package)_sha256_hash=fc014bd74727c1d5d30b396813685012c965d079244dd07b53bc1c75c610a2cb
 $(package)_dependencies=native_capnp
 
 define $(package)_config_cmds