fix: do not error out if OpenAI response has no delta

src/lib/apis/streaming/index.ts

@@ -36,7 +36,7 @@ async function* openAIStreamToIterator(
 						const data = JSON.parse(line.replace(/^data: /, ''));
 						console.log(data);
 
-						yield { done: false, value: data.choices[0].delta.content ?? '' };
+						yield { done: false, value: data.choices?.[0]?.delta?.content ?? '' };
 					} catch (e) {
 						console.error('Error extracting delta from SSE event:', e);
 					}