Fix empty channel detail format in management api

[Syuparn]

Proposed Changes

This fixes the response body format of management API GET /api/queues/%2f/{queuename}. While a channel is being deleted, the API returns an empty object as field .consumer_details[].channel_details so that SDK deserializers can handle this.

Close: #2684

# empty channel_detail is formatted as empty object
$ curl -s http://guest:guest@localhost:15672/api/queues/%2f/queue1 | jq .consumer_details[].channel_details
{
  "connection_name": "172.28.0.1:33550 -> 172.28.0.2:5672",
  "name": "172.28.0.1:33550 -> 172.28.0.2:5672 (1)",
  "node": "rabbit@d088896b1c04",
  "number": 1,
  "peer_host": "172.28.0.1",
  "peer_port": 33550,
  "user": "guest"
}
{}

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes issue Inconsistent type for channel_details when requesting queue admin data #2684)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

Checklist

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Further Comments

The response body above is checked by local Docker image bazel/packaging/docker-image:rabbitmq.

[michaelklishin]

@Syuparn thank you 🙏