Payload property named message breaks with null value

**Payload property named message breaks with null value**

``` "payload": {
"type": "object",
"properties": {
"message": {
"type": ["string", "null"],
"maxLength": 50
}
},
"required": ["message"],
},
"examples": [{
"name": "return",
"payload": {
"message": null
}
}
]
}
```

It breaks rendering of the asyncapi spec, validation does not give valid errors and studio.asyncapi.com breaks

**Expected result**
It works and renders. Note that this works if the message property is renamed or given a non null example value.

**Actual result**

The following error is given
```
Error thrown during AsyncAPI document validation. Name: Error, message: jsonPath: Cannot read properties of null (reading 'schemaFormat'): _$_property === 'message' && _$_v.schemaFormat === void 0, stack: Error: jsonPath: Cannot read properties of null (reading 'schemaFormat'): _$_property === 'message' && _$_v.schemaFormat === void 0 at v._eval (https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4494941) at https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4491179 at https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4493697 at Array.forEach () at v._walk (https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4493676) at v._trace (https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4491130) at v._trace (https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4490522) at https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4490621 at https://studio.asyncapi.com/static/js/main.f7f7093d.js:2:4493697 at Array.forEach ()
```

**Steps to reproduce**

Paste the following gist into the asyncapi studio
https://gist.github.com/ly29/6b56cc8252ad48ac681f19ea468d540f

**Troubleshooting**
I have reduced the issue down to one specific property that breaks.