Spring AI Add isPreventDefaultMerge flag for models options

I think this issue has more to do with #3253.

As far as I understand, in each model, if we set a parameter as null in its Options, it will be pulled from global parameters. Like here:

Prompt buildRequestPrompt(Prompt prompt) {
...
    // Define request options by merging runtime options and default options
    OpenAiChatOptions requestOptions = ModelOptionsUtils.merge(runtimeOptions, this.defaultOptions,
            OpenAiChatOptions.class);
...

However, if we don't want to pull from global parameters? Like in the issue I specified, the user doesn't want to change the global parameters, but needs to specify null for temperature?

Help me if I understand something wrong, however, as I understand it would be good for us if we add something like a flag to the options, let's say isPreventDefaultMerge and then our options would not merge.

If I understand this correctly and if this makes sense to you, I would be happy to work on it, thanks for your time