Add 'pipeline' attribute to processor metrics #22884

Job	Run time
govulncheck	25s
setup-environment	9s
lint	3m 41s
checks	1m 55s
cross-build-collector (darwin, amd64)	56s
cross-build-collector (darwin, arm64)	53s
test-coverage	3m 58s
cross-build-collector (linux, 386)	42s
unittest-matrix (ubuntu-latest, ~1.23)	2m 34s
unittest-matrix (ubuntu-latest, ~1.22)	2m 31s
cross-build-collector (linux, amd64)	45s
cross-build-collector (linux, arm64)	58s
cross-build-collector (linux, ppc64le)	42s
cross-build-collector (linux, arm, 7)	43s
cross-build-collector (linux, s390x)	50s
cross-build-collector (windows, 386)	46s
cross-build-collector (windows, amd64)	55s
unittest	1s
	23m 24s

Provide feedback