style: remove unnecessary semicolon after namespace #19275

Job	Run time
build_make (ubuntu:25.10)	5m 10s
build_make (ubuntu:24.04)	4m 28s
build_make (alpine:3.23)	6m 8s
build_cmake (alpine:3.23, false, false)	4m 33s
build_cmake (ubuntu:25.10, true, true)	5m 38s
build_cmake (ubuntu:24.04, true, true)	5m 30s
	31m 27s

Provide feedback