Feature: Add link to API implementation documentation instead of invalid API key error.

[dwestjohn]

Hello!

PyGWalker has been very useful for creating quick visualizations within jupyter notebook!

I noticed that when you try using the AI request tool, an API key error pops up when the feature is not properly set up through the Kanaries portal.

It may be beneficial for new users to have the setup link and a quick explanation displayed if a user tries using the feature without the key. This would save time for the user during the initial setup.

Thanks for all of your work!