When validating the openapi spec we were getting the following errors:
```
{
"messages": [
"attribute paths.'/categories.json'(post).responses.200.content.'application/json'.schema. is not of type `object`",
"attribute paths.'/categories/{id}.json'(put).responses.200.content.'application/json'.schema. is not of type `object`",
"attribute paths.'/c/{id}/show.json'(get).responses.200.content.'application/json'.schema. is not of type `object`",
"attribute paths.'/posts.json'(get).responses.200.content.'application/json'.schema.items is not of type `object`",
"attribute paths.'/groups/by-id/{id}.json'(get).operationId is repeated"
]
}
```
These changes resolve those openapi spec validation errors.
See:
https://github.com/discourse/discourse_api_docs/pull/139#issuecomment-3393138056
66c63774ac
