Make it easier to see avatar when equipping items

[saraolson]

When people change stuff like their body armor and have to scroll down a long list, they can easily see the change in their avatar without having to scroll up if the header is sticky

[saraolson]

alternatively we could do what web does and show a modal with the avatar and a preview of what they would look like with the gear on + confirmation button to actually equip it. this has the benefit of seeing something before committing to changing your equipment, but does introduce more taps.

if anyone has any preferences on the options here, please drop a comment!

[saraolson]

we plan to show the large avatar preview we implemented in avatar customizations to this view