Fix the tooltip centered when wrapping an avatar inside an avatar group

[newarifrh]

Summary

Make the tooltip centered on the avatar inside the avatar group.

Motivation

When using a tooltip for an avatar inside an avatar group, the tooltip is not centered. This issue occurs only on avatars inside the avatar group.

Changes Made

Added "tooltip" property to avatar theme.

Use of "tooltip" property based on "stacked" parameter. If "stacked=true" then the tooltip property will be sent for customization if using a tooltip.

However, if you keep using stacked without a tooltip, the behavior will remain the same.

Reference

fix #1231

---

• [x] I have followed the Your First Code Contribution section of the Contributing guide