Flow Graph - remove C++03 legacy #4713

Job	Run time
examples_clang-format	25s
copyright_check	15s
codespell	28s
python_module_test_ubuntu_latest	47s
ubuntu-24.04-arm_g++-14_cxx20_debug_preview=ON	56s
ubuntu-latest_g++_cxx14_relwithdebinfo_preview=OFF	4m 56s
ubuntu-22.04_g++_cxx17_release_preview=ON	1m 16s
ubuntu-24.04-arm_clang++_cxx20_release_preview=ON	1m 21s
windows_cl2022_cxx14_relwithdebinfo_preview=ON	8m 50s
ubuntu-22.04-arm_g++_cxx20_release_preview=ON-DBUILD_SHARED_LIBS=OFF	1m 18s
windows_cl2022_cxx17_relwithdebinfo_preview=OFF	8m 34s
examples_ubuntu-22.04_g++_cxx17_release_preview=ON	56s
windows_11_arm_cl2022_cxx20_release_preview=ON-DBUILD_SHARED_LIBS=OFF	8m 50s
examples_macos-15_clang++_cxx14_relwithdebinfo_preview=ON	52s
examples_ubuntu-24.04_g++_cxx20_debug_preview=ON	1m 6s
macos-15_clang++_cxx17_debug_preview=ON	47s
examples_windows_11_arm_cl2022_cxx14_relwithdebinfo_preview=ON	5m 36s
macos-14_clang++_cxx14_relwithdebinfo_preview=ON	50s
examples_windows_cl2022_cxx17_relwithdebinfo_preview=OFF	4m 37s
doc_examples_windows-2022_cl_cxx20_relwithdebinfo	2m 4s
doc_examples_ubuntu-latest_g++_cxx20_relwithdebinfo	50s
examples_ubuntu-latest_g++_cxx14_relwithdebinfo_preview=OFF	1m 0s
macos-13_clang++_cxx20_release_preview=ON-DBUILD_SHARED_LIBS=OFF	1s
documentation	0s
pages	-1s
	56m 34s

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