[Schema Inaccuracy] Invalid example for /repos/{owner}/{repo}/pulls/{pull_number}/codespaces requestBody

# Schema Inaccuracy

This is the JSON ref
```
#/paths/~1repos~1{owner}~1{repo}~1pulls~1{pull_number}~1codespaces/post/requestBody/content/application~1json/examples/default/value
```

Unrecognized field "ref"

The example has this
```
    1: {
>   2:   "ref" : "main",
    3:   "repository_id" : 1
    4: }
```

## Reproduction Steps

I found this in 
  - ghec
  - fpt
