fix: revert to IterableIterator type #2963

Job	Run time
build (18.x)	2m 33s
code-coverage (Abstractions, ./packages/abstractions/coverage)	1m 2s
build (20.x)	2m 4s
code-coverage (Authentication Azure, ./packages/authentication/azure/coverage)	1m 3s
build (22.x)	1m 51s
code-coverage (Authentication Spfx, ./packages/authentication/spfx/coverage)	1m 7s
code-coverage (Http Fetch, ./packages/http/fetch/coverage)	1m 7s
code-coverage (Serialization Form, ./packages/serialization/form/coverage)	1m 8s
code-coverage (Serialization JSON, ./packages/serialization/json/coverage)	1m 4s
code-coverage (Serialization Text, ./packages/serialization/text/coverage)	1m 9s
code-coverage (Serialization Multipart, ./packages/serialization/multipart/coverage)	1m 5s
code-coverage (Bundle, ./packages/bundle/coverage)	1m 7s
check-typescript-version-matrix	1s
publish-npm	0s
	16m 21s

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