Preserve in-progress message history when agent run errors #6145

Job	Run time
build-and-check	2m 57s
test-integration-packages/internal	1m 12s
test-integration-packages/billing	1m 14s
test-integration-sdk	1m 7s
test-integration-common	40s
test-integration-packages/agent-runtime	46s
test-integration-web	39s
test-.agents	46s
test-packages/internal	52s
test-web	1m 36s
test-cli	1m 7s
test-common	41s
test-packages/billing	39s
test-packages/agent-runtime	51s
test-integration-cli	40s
test-sdk	46s
	16m 33s

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