Kind of generalization of "User cannot be swapped with another user" ticket.

Steps:

1. Go to any content page
2. Click Locations tab
3. Click Select content item in Location Content Swap section
4. Navigate in the UDW and try to select users or articles (non-container contents)

Actual result:

It is impossible to swap locations with a non-container content.

Expected result:

It should be allowed to swap location with a non-container content.

Technical note:

As far as I understand the UDW module, that an error in configName passed in the ez_udw_config filter, in the ezplatform-admin-ui/src/bundle/Resources/views/themes/admin/content/tab/locations/panel_swap.html.twig:

    {{ form_widget(form.swap, {'attr': {
        'disabled': not can_swap,
        'class': 'btn btn-secondary btn--udw-swap ml-5',
        'data-udw-config': ez_udw_config('single_container', {})
    }}) }}

We use "single_container", where I would have use "single".