[Issue 4636][pulsar-dashboard] Count distinct bundles

[rshermanTHG]

Fixes #4636

Motivation

When looking at the Brokers page on the dashboard the number of bundles equalled the number of topics meaning 1 topic per bundle. This is incorrect.

Modifications

When counting the number of bundles set the distinct parameter to True.

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

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a followup issue for adding the documentation

Before this fix

After this fix

[merlimat]

👍