[Broker] Fix call sync method in async rest api for internalGetManagedLedgerInfo

[mattisonchao]

Motivation

Avoid call sync method in async rest API for PersistentTopicsBase#internalGetManagedLedgerInfo.

Modifications

• Use async instead of sync method.

Verifying this change

• Make sure that the change passes the CI checks.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (no)
• The public API: ( no)
• The schema: ( no )
• The default values of configurations: ( no)
• The wire protocol: ( no)
• The rest endpoints: (no)
• The admin cli options: (no)
• Anything that affects deployment: (no)

Documentation

• no-need-doc

[mattisonchao]

/pulsarbot rerun-failure-checks