Fetch user's token count in UserButton

### Is your feature request related to a problem? Please describe.

## Problem
In `SelectableItemDetail.kt` line 156, `UserButton` currently displays `user.numberOfTrees`
but there is an unresolved question about whether it should instead fetch and display
the user's token count.

## Location
`app/src/main/java/org/greenstand/android/TreeTracker/view/SelectableItemDetail.kt` line 156

## Suggested Fix
Determine whether token count should be fetched from the API and displayed here
instead of `numberOfTrees`, and implement accordingly.

### Describe the solution you'd like

Fetch the user's token count from the API and display it in the UserButton component in SelectableItemDetail.kt (line 156), replacing the current placeholder user.numberOfTrees value.

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

Start with app/src/main/java/org/greenstand/android/TreeTracker/view/SelectableItemDetail.kt at line 156 and trace how the user's data is obtained from the API. Confirm which token count should be used, then update UserButton so it displays that count instead of user.numberOfTrees; done means the correct token count is fetched and shown.

Written by the indexing model from the issue text.