Add gemini example using litellm #601

Job	Run time
find-tutorials	3s
test-10_async/10_temporal/020_state_machine	2m 23s
test-10_async/00_base/080_batch_events	3m 16s
test-10_async/00_base/010_multiturn	2m 8s
test-00_sync/000_hello_acp	2m 9s
test-10_async/00_base/030_tracing	2m 16s
test-10_async/00_base/000_hello_acp	2m 14s
test-10_async/00_base/040_other_sdks	3m 49s
test-10_async/10_temporal/000_hello_acp	2m 17s
test-00_sync/010_multiturn	2m 47s
test-10_async/10_temporal/090_claude_agents_sdk_mvp	2m 24s
test-10_async/10_temporal/060_open_ai_agents_sdk_hello_world	2m 28s
test-10_async/10_temporal/030_custom_activities	2m 12s
test-10_async/00_base/020_streaming	2m 22s
test-10_async/10_temporal/050_agent_chat_guardrails	2m 26s
test-10_async/10_temporal/100_gemini_litellm	2m 18s
test-10_async/10_temporal/080_open_ai_agents_sdk_human_in_the_loop	2m 32s
test-10_async/10_temporal/070_open_ai_agents_sdk_tools	2m 28s
test-00_sync/020_streaming	2m 54s
test-10_async/10_temporal/010_agent_chat	2m 40s
Test Summary	5s
	48m 11s

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