Convert asset balance to human readable format

After creating a new account and getting funds from the beta-4 faucet the balance on my account 0.5 ETH.

Running the command

```bash
forc wallet account 0 balance
```

The balance of the 0th account is shown as seen in the attached image.
The asset is `0x00...` and the displayed balance is `500000000` instead of something like `0.500000...`


In the following code snippet we should perform a check and format the value instead of iterating and directly displaying the value to the user.

https://github.com/FuelLabs/forc-wallet/blob/d6a4798f7159e807b9227f5a49f97179d9d2d0a7/src/account.rs#L259-L266