[Bug]: Sepolia network is not added in onboarding privacy setting screen

### Describe the bug

Sepolia network is not added in onboarding privacy setting screen, however Arbitrum Sepolia is added

### Expected behavior

Sepolia network added should appear

### Screenshots/Recordings

https://github.com/user-attachments/assets/d3e38693-2e38-47c2-a8d8-68a74ca91aac

### Steps to reproduce

1. Navigate to the onboarding privacy setting.
2. Try to add Sepolia network

### Error messages or log output

```shell

```

### Where was this bug found?

Internal release testing

### Version

13.20.0

### Build type

None

### Browser

Chrome

### Operating system

MacOS

### Hardware wallet

_No response_

### Additional context

_No response_

### Severity

_No response_

No file or test is named. First reproduce the issue in the onboarding privacy setting on the reported version, then trace the network-selection screen and its supported-network data. Done means Sepolia appears as an available network alongside Arbitrum Sepolia, with the relevant UI behavior verified.

Written by the indexing model from the issue text.