Avro schemas are not supported in the components/schemas section

### Describe the bug
Asyncapi supports Avro schemas, but only if they are in the message/payload section. It would be nice if we could put Avro schemas in the components/schemas section.

### To Reproduce
Steps to reproduce the behavior:
1. Create a document with an Avro schema in components/schemas. It will fail in the playground.

### Expected behavior
The document should parse as it does when the schema is in the message/payload section.

### Sample document

```yaml
asyncapi: 2.0.0
info:
title: Example with Avro
version: 0.1.0
channels:
example:
publish:
message:
schemaFormat: 'application/vnd.apache.avro;version=1.9.0'
payload:
$ref: '#components/schemas/mySchema'
components:
schemas:
mySchema:
type: record
doc: User information
fields:
- name: displayName
type: string
```

Reproduce the sample document in the AsyncAPI playground and compare it with the working message/payload placement. Trace how the components/schemas reference is handled, then verify that the sample document parses successfully with the Avro record in components/schemas.

Written by the indexing model from the issue text.