[fix][elasticsearch-sink] Handle Avro collections native types (GenericData.Array and Utf8 map keys)

[nicoloboschi]

Motivation

Avro native objects for Arrays and Maps are not supported by the sink.

If you try to use a Java POJO with a java.util.List/java.util.Set field with Avro Schema, you get:

022-04-26T11:56:51.477776276Z Caused by: java.lang.ClassCastException: class org.apache.avro.generic.GenericData$Array cannot be cast to class [Ljava.lang.Object; (org.apache.avro.generic.GenericData$Array is in unnamed module of loader 'app'; [Ljava.lang.Object; is in module java.base of loader 'bootstrap')
2022-04-26T11:56:51.477782027Z 	at org.apache.pulsar.io.elasticsearch.JsonConverter.toJson(JsonConverter.java:90) ~[?:?

For java.util.Map

ERROR org.apache.pulsar.io.elasticsearch.ElasticSearchSink - write error:
2022-04-26T12:03:34.776219894Z java.lang.IllegalArgumentException: Error while converting a value of type class java.util.HashMap to a MAP: java.lang.ClassCastException: class org.apache.avro.util.Utf8 cannot be cast to class java.lang.String (org.apache.avro.util.Utf8 is in unnamed module of loader 'app'; java.lang.String is in module java.base of loader 'bootstrap')

Modifications

• Handle GenericData.Array instances
• Handle Map with UUID as entry key

• no-need-doc

[nicoloboschi]

/pulsarbot rerun-failure-checks

[nicoloboschi]

@lhotari @dlg99 @eolivelli PTAL

[nicoloboschi]

/pulsarbot rerun-failure-checks