Fixes #38179 - Remove duplicates for multiCV hosts & activation keys

[pavanshekar]

What are the changes introduced in this pull request?

Addresses the issue of duplicate relations for hosts and activation keys in multi-content-view (multiCV) scenarios. Specifically, it ensures that duplicate entries are removed for both hosts and activation keys when retrieving content views, thus improving data accuracy and efficiency.

Considerations taken when implementing this change?

Careful consideration was given to the fact that the content views have many-to-many relationships with hosts and activation keys through intermediate associations. This required applying uniqueness filtering without causing errors, such as the composite error related to ActiveRecord associations.

What are the testing steps for this pull request?

1. Have a content view associated with multiCV hosts and/or multiCV activation keys
2. The multiple CVEs on the hosts/AKs must be the same CV / different LCE

And then...

1. Go to Content -> Lifecycle -> Content Views
2. Expand the CV details
3. The correct count should be displayed for Hosts and Activation Keys
4. The content views API response 'hosts' and 'activation_keys' nodes does not list duplicate hosts/AKs

[jturel]

Would it be appropriate to use distinct in the default scope? https://guides.rubyonrails.org/association_basics.html#distinct

[jeremylenz]

Would be great to have unit tests for this too :)

[pavanshekar]

Ack...I have added the unit tests

[jeremylenz]

Works as advertised, and thanks for adding the test!

ACK 👍