Feature/Use None instead of Optional #5800

Job	Run time
Build sdist and set version	41s
Build and test in Conda (ubuntu)	2m 43s
Build and test in Conda (windows)	5m 26s
build-cpp-test-linux (debug, gcc)	17m 59s
build-cpp-test-macos (debug)	7m 2s
build-cpp-test-linux (debug, clang)	11m 30s
build-cpp-test-macos (release)	10m 13s
build-cpp-test-linux (release, gcc)	34m 5s
build-cpp-test-windows (debug, msvc)	14m 1s
build-cpp-test-windows (debug, clang-cl)	16m 35s
build-cpp-test-linux (release, clang)	19m 48s
build-cpp-test-windows (release, msvc)	20m 13s
build-cpp-test-windows (release, clang-cl)	20m 35s
build-and-test-python (linux-x64)	10m 30s
build-and-test-python (linux-aarch64)	38m 58s
build-and-test-python (macos)	7m 49s
build-and-test-python (windows)	10m 1s
publish-wheels	8s
	4h 8m 17s

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