Win: Work Around MSVC ICE

[ax3l]

• CXXFLAGS: CI: Win Remove old Workaround impactx#893 -- no difference
• Build in RelWithDebInfo ?
• Disable pybind11 LTO?
• build with ClangCl?

Attempt to fix #1 - internal compiler error (ICE) in MSVC:

2025-03-14T18:18:31.9548460Z          "D:\a\impactx-wheels\impactx-wheels\src\build\temp.win-amd64-cpython-39\Release\Release\pyImpactX.vcxproj" (default target) (5) ->
2025-03-14T18:18:31.9548949Z          (Link target) ->
2025-03-14T18:18:31.9549826Z            d:\a\impactx-wheels\impactx-wheels\src\src\python\wakeconvolution.cpp : fatal error C1001: Internal compiler error. [D:\a\impactx-wheels\impactx-wheels\src\build\temp.win-amd64-cpython-39\Release\Release\pyImpactX.vcxproj]
2025-03-14T18:18:31.9551023Z            LINK : fatal error LNK1000: Internal error during IMAGE::BuildImage [D:\a\impactx-wheels\impactx-wheels\src\build\temp.win-amd64-cpython-39\Release\Release\pyImpactX.vcxproj]