[Bug]: cant change chain id after rpc url added

### Describe the bug

after an rpc url is set the chain id option is blanked out in edit

### Expected behavior

i can change the chain id after setting it

### Screenshots/Recordings


### Steps to reproduce

add localhost to network (or bring it back as default :pray: )
set it to 31337
go back in the edit ellipsis
try to set it to 1337

### Error messages or log output

_No response_

### Detection stage

In production (default)

### Version

12.6.0

### Build type

None

### Browser

Chrome

### Operating system

Linux

### Hardware wallet

_No response_

### Additional context

_No response_

### Severity

_No response_

Start from the network edit flow described in the reproduction steps, focusing on how the RPC URL and chain ID fields are populated and updated. Reproduce the issue with localhost, first setting chain ID 31337 and then attempting to change it to 1337. Done means the chain ID remains editable after an RPC URL has been added and the new value is saved.

Written by the indexing model from the issue text.