etcd(ticdc): retry on goaway to be more robust to pd restart

[3AceShowHand]

What problem does this PR solve?

Issue Number: close #6720

What is changed and how it works?

retry on the reported error. reference:

googleapis/google-cloud-go#4257

Check List

Tests

• Unit test

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

`None`.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• sdojjy
• zhaoxinyu

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[3AceShowHand]

/run-all-tests

[3AceShowHand]

/merge

[ti-chi-bot]

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

Commit hash: d1a8743

[ti-chi-bot]

@3AceShowHand: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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[3AceShowHand]

/run-leak-test
/run-integration-test
/run-kafka-integration-test
/run-dm-integration-test
/run-dm-compatibility-test