Fix test of rendered properties AMS

Here the displayed properties that we're testing also rely on shops data (including the list of supplied properties), which is now cached for 15 seconds. We clear that cache entry so we can cleanly test only the caching of the properties AMS array.

spec/features/consumer/caching/darkwarm_caching_spec.rb

@@ -50,6 +50,9 @@ feature "Darkswarm data caching", js: true, caching: true do
       property.presentation = "Changed Property"
       property.save
 
+      # Clear timed shops cache so we can test uncached supplied properties
+      clear_shops_cache
+
       visit shops_path
 
       taxon_timestamp2 = CacheService.latest_timestamp_by_class(Spree::Taxon)
@@ -73,4 +76,9 @@ feature "Darkswarm data caching", js: true, caching: true do
   def expect_cached(key)
     expect(Rails.cache.exist?(key)).to be true
   end
+
+  def clear_shops_cache
+    cache_key = "views/#{CacheService::FragmentCaching.ams_shops[0]}"
+    Rails.cache.delete cache_key
+  end
 end