[Feature][Connector-V2] Postgresql support read TIMESTAMP_TZ

[yzeng1618]

#9785

Purpose of this pull request

Add support for reading TIMESTAMP_TZ type in Postgresql

Does this PR introduce any user-facing change?

No breaking change; stronger TIMESTAMP_TZ read/write consistency with graceful fallbacks for legacy drivers

How was this patch tested?

Unit tests: adjust type converter tests for Postgresql to expect TIMESTAMP_TZ
E2E: Postgresql TIMESTAMP_TZ (part-3) added/fixed; compare offset-included strings for losslessness
Build: modular build and local install; spotless formatting passed

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

[yzeng1618]

All revisions have been completed.

[Carl-Zhou-CN]

LGTM

[Carl-Zhou-CN]

+1