[Fix][Connector-V2] Fix indefinite blocking by adjusting stopping condition in kafka split reader

[xiaochen-zhou]

Purpose of this pull request

Fix indefinite blocking by adjusting stopping condition in split reader
refer: apache/flink-connector-kafka#100

Does this PR introduce any user-facing change?

no

How was this patch tested?

exist tests

Check list

• If any new Jar binary package adding in your PR, please add License Notice according
  New License Guide
• If necessary, please update the documentation to describe the new feature. https://github.com/apache/seatunnel/tree/dev/docs
• If you are contributing the connector code, please check that the following files are updated:
  1. Update plugin-mapping.properties and add new connector information in it
  2. Update the pom file of seatunnel-dist
  3. Add ci label in label-scope-conf
  4. Add e2e testcase in seatunnel-e2e
  5. Update connector plugin_config
• Update the release-note.

[Carl-Zhou-CN]

Great catch! Can we also add test cases for this?

[xiaochen-zhou]

Great catch! Can we also add test cases for this?

OK, I will try to add it.

[Carl-Zhou-CN]

Great catch! Can we also add test cases for this?

OK, I will try to add it.

Looking forward to it!