[Hotfix][CDC] Fix thread-unsafe collection container in cdc enumerator

[hailin0]

Purpose of this pull request

Fix thread-unsafe collection container in cdc enumerator

Does this PR introduce any user-facing change?

No

How was this patch tested?

The enumerator will receive concurrent access from multiple readers, including when restoring, so any connector-enumerator should use a thread-safe container.

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 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.

[hailin0]

@EricJoy2048 @Hisoka-X @ic4y

[Hisoka-X]

Why not use concurrent list like CopyOnWriteArrayList? Should be faster.

[hailin0]

CopyOnWriteArrayList is suitable for scenarios where there are very few writes, because the copy action is expensive