Remove namespace directives from util headers (#520) #3371

Job	Run time
lint / python-lint	7s
lint / shell-lint	15s
lint / clang-format	11s
ubuntu / clang-build (ubuntu-24.04)	2m 12s
ubuntu / clang-build (ubuntu-24.04-arm)	1m 53s
ubuntu / gcc-build (ubuntu-24.04, Debug)	1m 35s
mac / clang-build (Debug)	2m 25s
ubuntu / gcc-build (ubuntu-24.04-arm, Debug)	2m 57s
ubuntu / gcc-build (ubuntu-24.04, Release)	1m 24s
windows / msvc-build (Debug)	5m 42s
windows / msvc-build (Release)	3m 52s
ubuntu / gcc-build (ubuntu-24.04-arm, Release)	3m 46s
mac / clang-build (Release)	2m 10s
windows / clang-build	2m 25s
mac / clang-test	3m 17s
windows / clang-test	2m 6s
ubuntu / clang-test (ubuntu-24.04-arm)	5m 51s
ubuntu / clang-test (ubuntu-24.04)	5m 15s
ubuntu / clang-sanitizer-build (ubuntu-24.04)	1m 45s
ubuntu / gcc-test (ubuntu-24.04-arm)	5m 44s
ubuntu / gcc-test (ubuntu-24.04)	4m 57s
windows / msvc-test	3m 1s
ubuntu / clang-sanitizer-test (ubuntu-24.04)	2m 48s
mac / clang-test-extended	2m 31s
windows / clang-test-extended	2m 26s
windows / msvc-test-extended	1m 55s
ubuntu / clang-sanitizer-test-extended (ubuntu-24.04)	1m 58s
ubuntu / clang-test-extended (ubuntu-24.04)	3m 8s
ubuntu / clang-test-extended (ubuntu-24.04-arm)	4m 7s
ubuntu / gcc-test-extended (ubuntu-24.04-arm)	4m 0s
ubuntu / gcc-test-extended (ubuntu-24.04)	3m 51s
ubuntu / gcc-build-codecov	4m 48s
perf / ubuntu-gcc-build-perf-stats	1m 38s
pages / build-scoreboard	9s
pages / build-doxygen-xml	32s
pages / build-sphinx	35s
pages / deploy-pages	0s
	1h 37m 16s

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