[FLINK-28208][Connectors/Hive] Set parallelism for map operator in class HiveTableSink's method createBatchSink

[Myracle]

What is the purpose of the change

Set parallelism for map operator in class HiveTableSink's method createBatchSink in order to keep consistent with HiveTableSink. If not so, the operators in sink can not be chained togather.

Brief change log

• Set parallelism for map operator in class HiveTableSink's method createBatchSink

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

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

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)

[flinkbot]

CI report:

• 29757edbb5ff4ac651e8a663c60791b4af6f5447 Azure: SUCCESS

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• @flinkbot run azure re-run the last Azure build

[Myracle]

@luoyuxia Can you have a look? Thanks.