[C++] Add detail logs for schema related messages

[BewareMyPower]

Motivation

If broker failed to parse the schema, the logs of C++/Python client is poor because when C++ client handles the Error response, it doesn't print the message field that is filled by broker. On the other hand, if the InvalidSchemaDataException is thrown by StructSchemaDataValidator#throwInvalidSchemaDataException, the detail error message will be written to the exception's cause. The String that getMessage() returns is not enough

Modifications

• When tryAddSchema failed, add the exception cause's message to the error message that's sent to client.
• Print Error response's message field to logs.

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage. Take #9483 (which is to be fixed) as the example, before this PR, the client side's log is like

Received error response from server: IncompatibleSchema -- req_id: 0

After this PR, the client side's log will be

Received error response from server: IncompatibleSchema (Invalid schema definition data for AVRO schema caused by org.apache.avro.SchemaParseException: Undefined name: "array") -- req_id: 0

[BewareMyPower]

/pulsarbot run-failure-checks

[BewareMyPower]

/pulsarbot run-failure-checks

[BewareMyPower]

/pulsarbot run-failure-checks

[BewareMyPower]

/pulsarbot run-failure-checks

[BewareMyPower]

/pulsarbot run-failure-checks