support GPT-4-Turbo API Test unit

Author: caopengan

src/test/java/dev/ai4j/openai4j/chat/ChatCompletionStreamingTest.java

@@ -27,7 +27,7 @@ class ChatCompletionStreamingTest extends RateLimitAwareTest {
  private static final String USER_MESSAGE = "write exactly the following 2 words: 'hello world'";
 
  private final OpenAiClient client = OpenAiClient.builder()
- .openAiApiKey("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")
+ .openAiApiKey(System.getenv("OPENAI_API_KEY"))
  .proxy(new Proxy(HTTP, new InetSocketAddress("127.0.0.1",7890)))
  .logRequests()
  .logResponses()