sink: fix avro timezone (#1615)

[ti-srebot]

cherry-pick #1615 to release-4.0
You can switch your code base to this Pull Request by using git-extras:

# In ticdc repo:
git pr https://github.com/pingcap/ticdc/pull/1711

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/ticdc.git pr/1711:release-4.0-1f1e1aaf16e1

---

What problem does this PR solve?

• https://asktug.com/t/topic/69408/4

What is changed and how it works?

• Restore timezone information in Avro encoder.

Check List

Tests

• Unit test

• Integration test
  Related changes

• Need to cherry-pick to the release branch

Release note

• Fix time zone lost in Avro output.

[ti-srebot]

/run-all-tests

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• amyangfei
• leoppro

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[amyangfei]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: cb4dd8f

[amyangfei]

/run-all-tests

[amyangfei]

/run-unit-tests