Issue with schema converter when encountered with specific type of schema

[SimplytheVinay]

Bug
Issue with schema Converter when encountered with specific type of schema

Steps to reproduce the behavior:

1. Check following local code which i am wrote to replicate behaviours we faced in Dev. I am passing avro file and using schema converter method
2. convertPulsarAvroSchemaToNonNullSchema of SchemaConverter.java gets called with schema
3. convertPulsarAvroSchemaToNonNullSchema, loops through the fields and calls convertOneField with each field name with schema
4. convertOneField method of SchemaConverter.java class take each field and converts the data
5. After going through the avro file when it encounters a specific type of union it goes into below code block and gives the error in else block
   https://github.com/streamnative/pulsar-io-lakehouse/blob/master/src/main/java/org/apache/pulsar/ecosystem/io/lakehouse/common/SchemaConverter.java#L153
6. Here is the schema which gives error:
   ["null",{"type":"map","values":["null","int","long","string","boolean","float","double"]},"int","long","string","boolean","float","double"]
7. See error

Expected behavior
This utility should handle such schema as well. While using the same avro file through some other online utilities, I was able to get proper JSON file with data.
https://dataconverter.io/convert/avro-to-json

Screenshots
Test code written to debug the failure locally

Code section which gives error

Environment

• OS: Mac and Ubuntu
• Pulsar version: 3.3.0.5
• Deployment: standalone and development env with pulsar and hudi connected

Additional context
This conversion is being done to source data from pulsar topic and to load it in HUDI. Another interesting thing is Pulsar storage sink connector is able to load this data in Bigquery without any issues.