Document Sessions.

We need to document the sessions that are listed in Chat on the right side, and under Automate > Agent sessions.

We also need to fix the docs that incorrectly say Automate > Sessions or Agent sessions.

The Chat page is specific to the user:

And the left sidebar page is where someone (with sufficient permissions...need to check what those are) can check out all Duo Agent Platform activity on their project. Kind of an admin-y feature