Feat/added chattBaiduWenxin chat model

[Mubashirshariq]

Fixes: #2751
Added ChatBaiduWenxin chat model

[HenryHengZJ]

thank you! some linting issue

[iceycc]

Thanks for you code, I used it。but It seems to require two keys, and need streaming。 like：

        const obj: Partial<ChatBaiduWenxin> = {
            streaming: true,
            baiduApiKey,
            baiduSecretKey,
            modelName,
            temperature: temperature ? parseFloat(temperature) : undefined
        }

    }

[Mubashirshariq]

@iceycc i have done the required changes

[iceycc]

In langchanJs , Wenxin becomes Qianfan, here , and then I refer to yours and it says an error ： stream.getReader is not a function。

See details here：
#2786