Adjust AI clients and services for MiniMax

Related issue： https://jihulab.com/gitlab-cn/gitlab/-/issues/3358

What does this MR do and why?

• Add MiniMax support for Summarize MR Changes；
• Add Timeout to ChatGLM client；
• Replace AI provider switching with ENV var；
• Fix MiniMax client logger；

Screenshots or screen recordings

How to set up and validate locally

Turn on Summarize MR Changes FF：!1864 (merged)

Config MiniMax ENV：!1907 (merged)

LLM_DEBUG=true
JH_AI_PROVIDER=mini_max
CHAT_MINIMAX_GROUP_ID=
CHAT_MINIMAX_API_KEY=

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.