REST Endpoint - Unable to modify

### Version Information

Server Version:
CLI Version (for CLI related issue): v2.12.0, v2.13.0-beta.1

### Environment

Ubuntu, OSS Docker + Caddy as Proxy

### What is the current behaviour?

When you edit a REST endpoint and click Modify Hasura tries to save to https://data.undefined/v1/graphql instead of correct endpoint. Creating a new endpoint still works.

### What is the expected behaviour?

Click Modify and it will save the current or modified GraphQL Request

### How to reproduce the issue?

1. Go to API > REST > Select a endpoint > Edit endpoint
2. Click Modify
3. Network requests will go to data.undefined

### Screenshots or Screencast

### Please provide any traces or logs that could help here.

N/A

### Any possible solutions?

No

### Can you identify the location in the source code where the problem exists?

No

### If the bug is confirmed, would you be willing to submit a PR?

No

### Keywords

- data.undefined
- REST
- Endpoint

Start in the API > REST endpoint edit flow and reproduce the Modify action while inspecting network requests. Trace why editing targets data.undefined/v1/graphql instead of the configured endpoint; done means saving the current or modified GraphQL request uses the correct endpoint, while creating a new endpoint still works.

Written by the indexing model from the issue text.