fix: handle MSVC warning C4866: compiler may not enforce left-to-right evaluation order

[XuehaiPan]

Description

Original error: https://github.com/metaopt/optree/actions/runs/14840166206/job/41660965730?pr=214#step:10:981

Same background (ChatGPT): https://chatgpt.com/share/681d0822-ce30-8008-89a9-74568143f1ee

Copy of error (so search engines pick this up in the future):

C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Microsoft\VC\v170\Microsoft.CppBuild.targets(1395,5): warning MSB8012: TargetPath(C:\Users\RUNNER~1\AppData\Local\Temp\tmpxvs51ag7.build-lib\optree\_C.cp39-win_amd64.pyd) does not match the Linker's OutputFile property value (C:\Users\RUNNER~1\AppData\Local\Temp\tmpxvs51ag7.build-lib\optree\_C.cp39-win_amd64.pyd). This may cause your project to build incorrectly. To correct this, please make sure that $(OutDir), $(TargetName) and $(TargetExt) property values match the value specified in %(Link.OutputFile). [C:\Users\RUNNER~1\AppData\Local\Temp\tmpat300luf.build-temp\Release\src\_C.vcxproj]
       Creating library C:/Users/RUNNER~1/AppData/Local/Temp/tmpat300luf.build-temp/Release/_C.lib and object C:/Users/RUNNER~1/AppData/Local/Temp/tmpat300luf.build-temp/Release/_C.exp
    Generating code
  C:\Users\runneradmin\AppData\Local\Temp\pip-build-env-cdc2qymv\overlay\Lib\site-packages\pybind11\include\pybind11\detail\function_record_pyobject.h(191): error C2220: the following warning is treated as an error [C:\Users\RUNNER~1\AppData\Local\Temp\tmpat300luf.build-temp\Release\src\_C.vcxproj]
  C:\Users\runneradmin\AppData\Local\Temp\pip-build-env-cdc2qymv\overlay\Lib\site-packages\pybind11\include\pybind11\detail\function_record_pyobject.h(191): error C2220: the following warning is treated as an error [C:\Users\RUNNER~1\AppData\Local\Temp\tmpat300luf.build-temp\Release\src\_C.vcxproj]
  C:\Users\runneradmin\AppData\Local\Temp\pip-build-env-cdc2qymv\overlay\Lib\site-packages\pybind11\include\pybind11\detail\function_record_pyobject.h(191): error C2220: the following warning is treated as an error [C:\Users\RUNNER~1\AppData\Local\Temp\tmpat300luf.build-temp\Release\src\_C.vcxproj]
  C:\Users\runneradmin\AppData\Local\Temp\pip-build-env-cdc2qymv\overlay\Lib\site-packages\pybind11\include\pybind11\detail\function_record_pyobject.h(191): warning C4866: compiler may not enforce left-to-right evaluation order for call to 'pybind11::detail::object_api<pybind11::handle>::operator[]' [C:\Users\RUNNER~1\AppData\Local\Temp\tmpat300luf.build-temp\Release\src\_C.vcxproj]

Suggested changelog entry: