add addAgentStep to sdk impl #4007

Job	Run time
build-and-check	2m 36s
test-.agents	31s
test-common	33s
test-backend	29s
test-cli	33s
test-web	32s
test-npm-app	36s
test-packages/agent-runtime	47s
test-integration-cli	37s
test-integration-common	32s
test-integration-.agents	36s
test-integration-npm-app	31s
test-integration-packages/agent-runtime	30s
test-integration-web	40s
test-integration-backend	39s
	10m 42s

Provide feedback