[pulsar-broker] Fix delete empty namespace with partitioned-topic metadata

[rdhabalia]

Motivation

Right now, broker gives below error while deleting empty namespace without any topic under the namespace but namespace was having partitioned-topic metadata.

pulsar-admin namespaces delete prop/us-west/my-ns
Cannot delete non empty namespace

Reason: Cannot delete non empty namespace

Modification

It's because broker was incorrectly assuming topic existence by checking partitioned-topic metadata. delete-admin API cleans up partitioned-metadata after successfully deleting namespace and it it should not incorrectly depend on partitioned-metadata check. this issue is already fixed with forcefully delete-ns admin-api and delete-admin also needs the same fix.

Result

User can delete namespace after successfully deleting all topics under the namespace.

[github-actions]

@rdhabalia:Thanks for your contribution. For this PR, do we need to update docs?
(The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[Anonymitaet]

@rdhabalia is this a bug fix and we do not need to update docs?

[rdhabalia]

this PR doesn't need doc update.

[github-actions]

The pr had no activity for 30 days, mark with Stale label.

[github-actions]

The pr had no activity for 30 days, mark with Stale label.

[dlg99]

@rdhabalia LGTM but the PR needs rebasing

[315157973]

There must be an exception, so a fail() should be added here

[github-actions]

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