Dledger mode,before broker role change,first unregister metadata on nameserver

[LittleBoy18]

Make sure set the target branch to develop

What is the purpose of the change

Dledger mode broker status abnormal #3168

Brief changelog

XX

Verifying this change

XXXX

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[coveralls]

Coverage decreased (-0.03%) to 53.897% when pulling f5be0aefbcbe96abb4c3fb434311646fd055742b on LittleBoy18:fix-DledgerBrokerRole into a20f31bb3de242756542c552d7212a7a40000ba4 on apache:master.

[github-actions[bot]]

This PR is stale because it has been open for 365 days with no activity. It will be closed in 3 days if no further activity occurs. If you wish not to mark it as stale, please leave a comment in this PR.

[github-actions[bot]]

This PR was closed because it has been inactive for 3 days since being marked as stale.