Use datetime.timedelta in openai_agents samples (#312) #1229

Job	Run time
build-lint-test (3.14, macos-intel)	10m 31s
build-lint-test (3.14, macos-arm)	6m 6s
build-lint-test (3.10, ubuntu-latest)	5m 45s
build-lint-test (3.10, macos-arm)	8m 21s
build-lint-test (3.10, macos-intel)	10m 59s
build-lint-test (3.14, windows-latest)	7m 48s
build-lint-test (3.14, ubuntu-latest)	6m 22s
build-lint-test (3.10, windows-latest)	6m 34s
	1h 2m 26s

Provide feedback