[Fix][Flink] Cache writer states during commit preparation to fix streaming mode lost data.

[Adamyuanyuan]

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Purpose of this pull request

#9826

• Fix the Flink translation semantics for SeaTunnel v1 sinks when running on Flink 1.15/1.16 Streaming, where File/Hive sinks could lose data or fail with source missing during commit.
• Ensure that, from the SeaTunnel sink’s perspective, prepareCommit(checkpointId) and snapshotState(checkpointId) are executed back‑to‑back for the same checkpoint inside FlinkSinkWriter, removing the race where data is still written into the old transaction directory after prepareCommit.
• Keep the change local to seatunnel-translation-flink-common (FlinkSinkWriter), preserving existing behavior for Flink 1.13/1.14 and the dedicated Flink 1.20 translation module, and add unit tests to lock in the new semantics.

Does this PR introduce any user-facing change?

no

How was this patch tested?

UT

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 necessary, please update incompatible-changes.md to describe the incompatibility caused by this PR.
• 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

[Adamyuanyuan]

#9826