[Bug]: User can swap negative numbers on the modal

### Pre-flight checklist

- [x] I searched existing issues and didn't find a duplicate.
- [x] I tried a hard reload (Cmd/Ctrl + Shift + R) and the bug persists.
- [x] I tried in an incognito/private window and the bug persists.

### Bug Type

UI / Visual (layout, styling, responsiveness)

### Severity

Critical — site down, data loss, security

### Page / Area

Homepage (/)

### URL

https://decentraland.zone/account/wallets

### Environment

None

### Description

User can swap negative numbers on the modal

### Frequency

None

### Regression?

No — never worked / new feature

### Last known working version / date

_No response_

### Steps to Reproduce

1. Go to zone
2. Click on wallet
3. Click on swap
4. Check that you can lower the numbers less than 0

### Expected Behavior

User should not wap negative numbers on the modal

### Actual Behavior

User can swap negative numbers on the modal

### Browser

Chrome

### Browser version

_No response_

### Operating System

macOS

### OS version

_No response_

### Device type

Desktop

### Site language

None

### Authentication Method

None

### Auth Details

_No response_

### Blockchain Network

None

### Screenshots / Screen Recording

### Console Errors

```shell

```

### Failed Network Requests

```shell

```

### HAR file

_No response_

### Additional Context

_No response_