agent: Simplify user message design (#29165)

Mainly removing the "You" label, which didn't add a lot of value. Still
figuring out an issue with font size Markdown rendering before merging
this PR.

Release Notes:

- N/A
109f1d43fcDanilo Leal committed on 4/22/2025, 12:51:50 PM· committed by GitHubparenta5852d4
1 file changedLine totals unavailable