[Improve][connector-cdc-mysql] avoid listing tables under unnecessary databases

[lvyanquan]

Purpose of this pull request

skip list tables in unnecessary databases
inspired by apache/flink-cdc#2160

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.

[Hisoka-X]

Thanks @lvyanquan LGTM, cc @hailin0 @ic4y

[liugddx]

+1