Added new feature popover to saved replies dropdown

What does this MR do and why?

Added a new feature popover to the saved replies dropdown toggle

Related to Saved replies frontend work (#355845 - closed)

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

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.