FE: Display agent details in a popover

MR: Resolve "FE: Display agent details in a popover" (!165851 - merged)

Description

As a group maintainer, owner or instance admin, I want to see a cluster agent's status, number of connected workspaces, and creation date in the mapped agents table so I can have a better understanding of the agent.

NOTE: For this issue, we do NOT need to display the number of workspaces, as that requires more design and backend work.

Acceptance Criteria

• The agent details are displayed in a popover component.
• The agent status is indicated using a badge component.

Design Requirements