Explicitly filter out unpublished collections

Ref #71

config/sync/views.view.collection.yml

@@ -131,7 +131,43 @@ display:
           use_highlighting: false
           multi_type: separator
           multi_separator: ', '
-      filters: {  }
+      filters:
+        status:
+          id: status
+          table: search_api_index_collection
+          field: status
+          relationship: none
+          group_type: group
+          admin_label: ''
+          operator: '='
+          value: '1'
+          group: 1
+          exposed: false
+          expose:
+            operator_id: ''
+            label: ''
+            description: ''
+            use_operator: false
+            operator: ''
+            identifier: ''
+            required: false
+            remember: false
+            multiple: false
+            remember_roles:
+              authenticated: authenticated
+          is_grouped: false
+          group_info:
+            label: ''
+            description: ''
+            identifier: ''
+            optional: true
+            widget: select
+            multiple: false
+            remember: false
+            default_group: All
+            default_group_multiple: {  }
+            group_items: {  }
+          plugin_id: search_api_boolean
       sorts:
         created:
           id: created