[DSRN] Added AvatarFavicon

[brianacnguyen]

Description

This PR adds the AvatarFavicon component to DSRN.

Related issues

Fixes: #367

Manual testing steps

1. Run yarn storybook:ios from root
2. Go to Components > AvatarFavicon

Screenshots/Recordings

Before

After

Simulator.Screen.Recording.-.iPhone.15.Pro.Max.-.2025-02-27.at.16.03.35.mp4

Pre-merge author checklist

• I've followed MetaMask Contributor Docs
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.