Preserve in-progress message history when agent run errors #6146

Job	Run time
build-and-check	3m 0s
test-integration-packages/internal	1m 8s
test-integration-packages/billing	1m 6s
test-integration-web	39s
test-integration-cli	46s
test-integration-common	38s
test-integration-sdk	1m 3s
test-integration-packages/agent-runtime	46s
test-common	46s
test-packages/billing	48s
test-packages/agent-runtime	49s
test-.agents	44s
test-cli	56s
test-packages/internal	50s
test-sdk	40s
test-web	1m 37s
	16m 16s

Provide feedback