fix: fix stamp avatar case sensitiveness

[wa0x6e]

Summary

This PR fix an issue where the UserAvatar component was case sensitive, this considering 2 exact same addres, but with different case as different.

This PR will always checksummed the address

How to test

1. Go to http://localhost:8080/#/cowtesting.eth/delegates
2. Console inspect a random delegate with avatar
3. This avatar should have a timestamp params, and address is checksummed
4. Click on the card to go to delegate statement
5. The avatar in the sidebar should load immediately (since loaded from cache)
6. This avatar should have same same exact url as before (checksummed, and same timestamp params)

[ChaituVR]

utAck