Support `xhigh` thinking effort for certain OpenAI models

### Description

<img width="1318" height="860" alt="Image" src="https://github.com/user-attachments/assets/ba215827-c930-47d6-a93a-5832e54a4956" />
As shown in images, several models support xhigh thinking efforts.
So far I know gpt-5.2, gpt-5.2-codex, gpt-5.1-codex-max have `xhigh` option available