refactor: Remove "using namespace" in header files (#3255) #6761

Job	Run time
semantic_pull_request	2s
is_not_draft_pull_request	3s
are_submodules_in_sync	17s
baseline_log	4s
if_not_unassigned_pull_request	1s
code_coverage / build_test_deploy	45m 42s
Check code style / build_test_deploy	1m 17s
Check documentation / build_test_deploy	1m 5s
Ubuntu (20.04, gcc 10.5.0, open-mpi 4.0.3) - github codespaces / build_test_deploy	5m 7s
Ubuntu (20.04, gcc 9.4.0, open-mpi 4.0.3) / build_test_deploy	4m 57s
Ubuntu (22.04, clang 15.0.7, open-mpi 4.1.2) / build_test_deploy	3m 55s
Ubuntu (22.04, gcc 11.4.0, open-mpi 4.1.2) / build_test_deploy	5m 12s
Ubuntu (22.04, gcc 12.3.0, open-mpi 4.1.2) / build_test_deploy	4m 37s
Ubuntu CUDA (20.04, clang 10.0.0 + gcc 9.4.0, open-mpi 4.0.3, cuda-11.8.89) / build_test_deploy	6m 30s
Ubuntu debug (20.04, gcc 10.5.0, open-mpi 4.0.3) - github codespaces / build_test_deploy	10m 40s
Ubuntu CUDA debug (20.04, clang 10.0.0 + gcc 9.4.0, open-mpi 4.0.3, cuda-11.8.89) / build_test_deploy	4m 12s
run_integrated_tests / build_test_deploy	40m 39s
check_that_all_jobs_succeeded	1s
	2h 14m 21s

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