fix: typings for headers and tests #3513

Job	Run time
lint	27s
build	1m 54s
lib-tests (14.x, showcase)	2m 8s
lib-tests-esm (14.x, showcase)	2m 47s
lib-tests (14.x, kms)	1m 47s
lib-tests-esm (14.x, kms)	2m 34s
lib-tests (14.x, translate)	1m 35s
lib-tests-esm (14.x, translate)	2m 16s
lib-tests-esm (14.x, monitoring)	3m 10s
lib-tests (14.x, monitoring)	2m 28s
lib-tests-esm (14.x, dlp)	2m 53s
lib-tests (14.x, dlp)	2m 16s
lib-tests-esm (14.x, texttospeech)	2m 7s
lib-tests (14.x, texttospeech)	1m 30s
lib-tests-esm (14.x, showcase-legacy)	2m 14s
lib-tests-esm (14.x, compute)	2m 13s
lib-tests (14.x, showcase-legacy)	1m 24s
lib-tests-esm (14.x, logging)	3m 0s
lib-tests-esm (14.x, bigquery-v2)	2m 51s
lib-tests (14.x, compute)	1m 30s
lib-tests-esm (14.x, redis)	2m 15s
lib-tests (14.x, logging)	2m 16s
lib-tests (14.x, bigquery-v2)	2m 22s
lib-tests (14.x, redis)	1m 32s
	51m 29s

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