FIX: Strip whitespace from URL before validating (#12174)

lib/topic_retriever.rb

@@ -15,7 +15,7 @@ class TopicRetriever
   private
 
   def invalid_url?
-    !EmbeddableHost.url_allowed?(@embed_url)
+    !EmbeddableHost.url_allowed?(@embed_url.strip)
   end
 
   def retrieved_recently?

spec/components/topic_retriever_spec.rb

@@ -63,6 +63,11 @@ describe TopicRetriever do
         end
       end
     end
+
+    it "works with URLs with whitespaces" do
+      expect { TopicRetriever.new(" https://example.com ").retrieve }
+        .not_to raise_error
+    end
   end
 
 end