collection needs to be persisted to have an id

Setting the relationship of nested collections through Valkyrie resources in the CollectionMemberService requires that the parent collection have an id assigned to be able to store the id in the child.  The previous approach through AF took care of establishing the relationship.

spec/models/concerns/hyrax/collection_nesting_spec.rb

@@ -32,7 +32,7 @@ def after_save
     end
 
     let(:user) { create(:user) }
-    let!(:collection) { build(:collection_lw, collection_type_settings: [:nestable]) }
+    let!(:collection) { create(:collection_lw, collection_type_settings: [:nestable]) }
     let!(:child_collection) { create(:collection_lw, collection_type_settings: [:nestable]) }
     let(:extent) { Hyrax::Adapters::NestingIndexAdapter::FULL_REINDEX }