feat: allow to provide Guzzle middleware

[fan711]

This allows to provide middleware to Guzzle. For instance a debug logger:

$stack = HandlerStack::create();
$stack->push(\GuzzleHttp\Middleware::log(
    Log::getLogger(),
    new \GuzzleHttp\MessageFormatter('{method} {uri} {code} {req_body:?} {res_body:?}')
));

return new OpenAI(
    ...
    httpOptions: new HttpClientOptions(
        handler: $stack
    )
);

[lamberttraccard]

I have some weird behaviour since this change. I can't see any ToolCallMessage anymore.

Before:

After:

Is it something expected ?

[ilvalerione]

I think you introduced a bug. I didn't notice it because the PR was about the Guzzle provider, but you changed the logic in AbstractChatHistory that is inconsistent I think.

[ilvalerione]

Whay did you add the assistant role at line 205 of the AbstractChatHisotry?

[fan711]

I did not intend to add the second commit to the PR but I pushed it to the same branch so it still slipped in there.

In fact this line solved an issue for me when I have multiple assistant messages in a row. It should be acceptable because I hand the conversation between nodes and these assistant messages are internal 'thinking'. I know it was in earlier days required to have messages strictly alternating between user and assistant but I think it is not a requirement anymore - at least the OpenAI api accepts multiple messages per role.

Thus I propose to remove this restriction of alternating message roles altogether. But if it is not acceptable I would just do it in my fork and I'm sorry to have caused a bug.