Add coment to clarify usage in tool filter

What does this MR do and why?

In this MR, this adds a comment clarifying why we need to set the selected option when the GraphQL query is done populating.

Screenshots or screen recordings

The is no UI/UX changes

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.

Related to #371910 (closed)