[improve][admin]add comment for topic level admin interface parameters in geo-replication

[Coselding]

Motivation

Add comment for org.apache.pulsar.client.admin.Topics class.

Modifications

Add comment for "applied" parameter in org.apache.pulsar.client.admin.Topics#getReplicationClusters and org.apache.pulsar.client.admin.Topics#getReplicationClustersAsync.

Documentation

• [ ] doc
• [ ] doc-required
• [ ] doc-not-needed
• [x] doc-complete

[github-actions[bot]]

@Coselding Please add the following content to your PR description and select a checkbox:

- [ ] `doc` <!-- Your PR contains doc changes -->
- [ ] `doc-required` <!-- Your PR changes impact docs and you will update later -->
- [ ] `doc-not-needed` <!-- Your PR changes do not impact docs -->
- [ ] `doc-complete` <!-- Docs have been already added -->