Add support for structured output for AzureAIChatCompletionClient.

[ekzhu]

Confirmation

• I confirm that I am a maintainer and so can use this template. If I am not, I understand this issue will be closed and I will be asked to use a different template.

Issue body

See OpenAIChatCompletionClient for example.

[Sheikh1980]

Unlock my file

[irmadong]

Hi @ekzhu this is Jing. Can I claim this one? I will send the sketch here / through the discord. Thanks!