Simplify #pagy calls without default item counts

Pagy will pick up the :per_page param by default now, so we don't need to specify `items: params[:per_page]` unless we want to use something beyond that param's value.

app/controllers/admin/bulk_line_items_controller.rb

@@ -16,7 +16,7 @@ module Admin
         reorder('spree_line_items.order_id ASC, spree_line_items.id ASC')
 
       pagy = nil
-      pagy, @line_items = pagy(@line_items, items: params[:per_page]) if pagination_required?
+      pagy, @line_items = pagy(@line_items) if pagination_required?
 
       render json: {
         line_items: serialized_line_items,

app/controllers/api/v0/states_controller.rb

@@ -32,7 +32,7 @@ module Api
           includes(:country).order('name ASC')
 
         if pagination?
-          _pagy, states = pagy(states, items: params[:per_page])
+          _pagy, states = pagy(states)
         end
 
         states