Add SAA TemporalNexusOperation handling #5455

Job	Run time
check-protos	8m 26s
test-latest-deps	10m 46s
cloud-test	2m 3s
features-tests / test	6m 25s
build-lint-test (3.14, ubuntu-arm)	12m 42s
build-lint-test (3.10, ubuntu-latest)	14m 48s
build-lint-test (3.14, ubuntu-latest)	18m 35s
build-lint-test (3.10, macos-arm)	8m 14s
build-lint-test (3.14, windows-latest)	19m 46s
build-lint-test (3.14, macos-arm)	12m 24s
build-lint-test (3.10, ubuntu-arm)	11m 37s
build-lint-test (3.10, windows-latest)	22m 59s
	2h 28m 45s

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