[Bug]: Error provisioning domain

### Problem description

I am getting a production issue trying to add a domain.

### Steps to reproduce

1. go into the project in dash
2. try to add a domain
3. get the following error message

### Expected behavior

Not to get an error message and successfully add the domain.

### Environment

_No response_

### Possible solution

_No response_

### Additional context

_No response_

Start with the attached error screenshot and the reported Deno Deploy dashboard flow: open a project and try adding a domain. The payload names no source files or tests, so locating the provisioning entry point and confirming reproduction come first. Done means the domain can be added successfully without the reported error.

Written by the indexing model from the issue text.