Closes #46142

Release Notes:

- Fixed AI commit message button in Git panel being hidden instead of
disabled when no AI provider is configured. The button now remains
visible with a tooltip explaining how to enable the feature.

Screenshot:

<img width="90%" alt="Screenshot 2026-01-10 at 18 16 12"
src="https://github.com/user-attachments/assets/6af9c845-7857-40e1-bfb5-3118f1af8360"
/>

---------

Co-authored-by: Danilo Leal <daniloleal09@gmail.com>