[Bugfix] [connector-jdbc] Fix when type is int and null value will always get 0 instead of null

[choucmei]

Purpose of this pull request

Check list

• Code changed are covered with tests, or it does not need tests for reason:
• 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 change log that in connector document. For more details you can refer to connector-v2
  2. Update plugin-mapping.properties and add new connector information in it
  3. Update the pom file of seatunnel-dist
• Update the release-note.

[choucmei]

This PR was blocked by e2e because mysql e2e was losing data.
#4732

[EricJoy2048]

What problem is this PR trying to solve? Do you need to modify the title?

[EricJoy2048]

Please fix CI error.

[EricJoy2048]

LGTM, Should you add e2e test to test this pr?

[choucmei]

LGTM, Should you add e2e test to test this pr?

LGTM, Should you add e2e test to test this pr?

I will add e2e testing as soon as possible

[hailin0]

@choucmei
Please check ci error