[improve][pulsar-testclient] Add disableBatching as CLI argument for pulsar-perf-producer

[vineeth1995]

Motivation

The pulsar-perf-tool should be able to take "disableBatching" as an input argument as it can be provided by the user.

Modifications

Add an extra parameter to in the PerformanceProducer.java class.
Extract producerBuilder creation into a separate method.
Add unit testcase to verify if batching is disabled

Verifying this change

This change added tests and can be verified as follows:

-Added unit test to verify functionality with batching disabled

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: (no)
• The schema: (no)
• The default values of configurations: (no)
• The wire protocol: (no)
• The rest endpoints: (no)
• The admin cli options: (no)
• Anything that affects deployment: (no)

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