[Bug]: Fiat conversion toggle on test network not working as expected

### Describe the bug

When the fiat conversion toggle is enabled on the test network, the balance should be represented as $0, but instead it displays as $0.00.

### Expected behavior

Balance should display as $0.

### Screenshots/Recordings

https://github.com/user-attachments/assets/54fdfcce-f56e-4c98-aa80-b1124e601a08

### Steps to reproduce

1. Launch the app on a Sepolia test network.
2. Navigate to the settings and enable the Fiat Conversion toggle.
3. Observe the balance representation.

### Error messages or log output

```shell

```

### Detection stage

On main branch

### Version

7.56.0

### Build type

None

### Device

iphone

### Operating system

iOS

### Additional context

_No response_

### Severity

_No response_

Reproduce the issue on an iPhone using the Sepolia test network, then trace the fiat-conversion balance formatting from the settings toggle. Done means the enabled toggle displays a zero balance as $0 rather than $0.00.

Written by the indexing model from the issue text.