docs: update starter to ask for api key #6626

Job	Run time
Test on Node.js 18.x	53s
E2E on Node.js 18.x	1m 25s
Test on Node.js 20.x	51s
E2E on Node.js 20.x	1m 25s
Test on Node.js 22.x	47s
typecheck	1m 13s
E2E on Node.js 22.x	1m 16s
Build LlamaIndex Example (cloudflare-worker-agent)	47s
Test on Node.js 23.x	40s
E2E on Node.js 23.x	1m 42s
Build LlamaIndex Example (nextjs-agent)	1m 19s
Build LlamaIndex Example (nextjs-edge-runtime)	1m 22s
Build LlamaIndex Example (nextjs-node-runtime)	1m 23s
typecheck-examples	1m 40s
Build LlamaIndex Example (waku-query-engine)	51s
Build LlamaIndex Example (llama-parse-browser)	48s
	18m 22s

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