GenerationConfig being overwritten on ChatSession

[evandromurilo]

We do this on sendMessage:

        $config = (new GenerationConfig())
        ->withCandidateCount(1);
        $response = $this->model
            ->withGenerationConfig($config)
            ->generateContentWithContents($this->history);

Which overwrittes any previously defined generation config.

[evandromurilo]

#67