[Bug] Clicking 'produce message' on some avro-schemed topics breaks

[Haarolean]

Describe the bug

Clicking 'produce message' on some avro-schemed topics produces 502.

Set up docker, latest master

Steps to Reproduce Steps to reproduce the behavior:

1. set up reddit connector
2. go to topic reddit-posts-avro
3. click 'produce message'
4. ???
5. PROFIT

Expected behavior should work fine

Screenshots

Additional context

[iliax]

error occurs when converting recursive avro schema to json schema (stackoverflow in AvroJsonSchemaConverter) example failing schema

{
	"type": "record",
	"name": "Anything",
	"namespace": "io.confluent.connect.avro",
	"fields": [
		{
			"name": "somekey",
			"type": "string"
		},
		{
			"name": "recursion",
			"type":  "Anything"
		}
      ]
}