Fix test type errors in context-pruner, cost-aggregation, and agent-r… #5593

Job	Run time
build-and-check	2m 36s
test-integration-packages/internal	1m 10s
test-integration-packages/billing	1m 2s
test-integration-packages/agent-runtime	48s
test-integration-sdk	39s
test-integration-web	42s
test-packages/internal	48s
test-integration-cli	41s
test-.agents	46s
test-integration-common	45s
test-packages/agent-runtime	58s
test-common	37s
test-web	47s
test-sdk	53s
test-cli	2m 35s
test-packages/billing	43s
	16m 30s

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