Paginate posts and media items by `properties.uid` not `_id`

### Is your feature request related to a problem?

Not that #964 has been merged, need to update the existing pagination methods to use `properties.uid` and not `_id` (which is now a deprecated property).  

### Describe the solution you’d like

See #964.

### Describe alternatives you’ve considered

_No response_

### Additional context

_No response_