[improve][client] Reduce duplicate code in ConsumerBuilderImpl

[Pomelongan]

Motivation

There are duplicate codes in org.apache.pulsar.client.impl.ConsumerBuilderImpl#topic and org.apache.pulsar.client.impl.ConsumerBuilderImpl#topics, org.apache.pulsar.client.impl.ConsumerBuilderImpl#topicsPattern(java.util.regex.Pattern) and org.apache.pulsar.client.impl.ConsumerBuilderImpl#topicsPattern(java.lang.String).

Modifications

Merge the duplicate codes in org.apache.pulsar.client.impl.ConsumerBuilderImpl#topic and org.apache.pulsar.client.impl.ConsumerBuilderImpl#topics, org.apache.pulsar.client.impl.ConsumerBuilderImpl#topicsPattern(java.util.regex.Pattern) and org.apache.pulsar.client.impl.ConsumerBuilderImpl#topicsPattern(java.lang.String).

Verifying this change

• [x] Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

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

If the box was checked, please highlight the changes

• [ ] Dependencies (add or upgrade a dependency)
• [ ] The public API
• [ ] The schema
• [ ] The default values of configurations
• [ ] The binary protocol
• [ ] The REST endpoints
• [ ] The admin CLI options
• [ ] Anything that affects deployment

Documentation

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

Matching PR in forked repository

PR in forked repository: https://github.com/Pomelongan/pulsar/pull/13