[Kinesis] Fix null error messages in onFailure exception in KinesisSink.

[RobertIndie]

Motivation

Currently, if the kinesis producer fails to send a message, the error message in the exception in onFailure is null.
So the log output will look like below:

exception.getMessage() is null.
If the exception is UserRecordFailedException, we need to extract it to see real error messages.
The expected output is as follows:

[kpl-callback-pool-0-thread-0] ERROR org.apache.pulsar.io.kinesis.KinesisSink - [test-io] Failed to published message for replicator of Optional[persistent://public/default/test-kinesis-0]-Optional[420369924113]: Attempts:errorMessage:Unable to connect to endpoint with address : 3.15.36.110, errorCode:, delay:103, duration:12010;errorMessage:Unable to connect to endpoint, errorCode:, delay:54, duration:6005;errorMessage:Unable to connect to endpoint, errorCode:, delay:54, duration:6004;errorMessage:Unable to connect to endpoint, errorCode:, delay:50, duration:6004;errorMessage:Record has reached expiration, errorCode:Expired, delay:0, duration:0;

Modifications

• Extract the UserRecordFailedException to see real error messages

[sijie]

@eolivelli @codelipenghui I marked this issue for 2.7.2

[eolivelli]

Okay