Fix error handler with using unsubscribed response body in exception message in AnthropicApi class.

When an error occurs while calling the chatCompletionStream function, It's difficult to know the cause.

AS-IS RuntimeException's message is a toString of an object (Mono<String>).

Response exception, Status: [401 UNAUTHORIZED], Body:[checkpoint("Body from POST https://api.anthropic.com/v1/messages [DefaultClientResponse]")]

Spring-ai Fix error handler with using unsubscribed response body in exception message

TO-BE Replace the RuntimeException's message with the response body.

Response exception, Status: [401 UNAUTHORIZED], Body:[{"type":"error","error":{"type":"authentication_error","message":"invalid x-api-key"}}]

Spring-ai Fix error handler with using unsubscribed response body in exception message

Comment From: markpollack

Thanks! merged in fb2e7528d0b74ae4adcb4aa6e18436bff2e808e5