Fix flaky LangGraph timeout tests #5006

Job	Run time
test-latest-deps	10m 6s
cloud-test	1m 42s
check-protos	7m 54s
build-lint-test (3.10, ubuntu-arm)	10m 56s
features-tests / test	7m 54s
build-lint-test (3.10, ubuntu-latest)	13m 23s
build-lint-test (3.14, macos-intel)	17m 25s
build-lint-test (3.14, ubuntu-latest)	17m 25s
build-lint-test (3.10, windows-latest)	19m 8s
build-lint-test (3.14, windows-latest)	16m 41s
build-lint-test (3.10, macos-intel)	21m 31s
build-lint-test (3.14, ubuntu-arm)	10m 30s
build-lint-test (3.10, macos-arm)	7m 0s
build-lint-test (3.14, macos-arm)	6m 44s
	2h 48m 19s

Provide feedback