Constructor for Anthropic3ChatOptions is not public

[bruno-oliveira]

Bug description
When passing custom prompt ChatOptions to Anthropic3 model calls, since the constructor is not public, this means that the reflection and/or JSON merging properties can't happen, and the call would fail.

Environment
Sprint AI 1.0.0-M4
Java 21
Springboot 3.3.0

Steps to reproduce
Trying to set ChatOptions in a prompt call to the BedrockAnthropic3 model fails due to constructor lack of visibility.

Expected behavior
Options should be set and work correctly

Minimal Complete Reproducible example

chatModel.stream(new Prompt(messages, ChatOptionsBuilder.setTemperature(0.0).build()));

fails if the underlying model is from Anthropic3 bean-family.

[bruno-oliveira]

#1919

FYI @markpollack @tzolov