Update docs for the Agent creation flow

What does this MR do and why?

This MR slightly updates the agent installation flow documentation as well as the agents' list screenshot to reflect the changes of the Kubernetes section UX.

you can see all the related changes in the MR !71482 (closed)

Screenshots or screen recordings

Here is the updated screenshot

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.

Related to #340759 (closed)