Use atomUri in Undo activity of Announce (#5376)

This allows deletion of reblogs which delivered before with OStatus URI.

spec/lib/activitypub/activity/undo_spec.rb

@@ -25,16 +25,30 @@ RSpec.describe ActivityPub::Activity::Undo do
           type: 'Announce',
           actor: ActivityPub::TagManager.instance.uri_for(sender),
           object: ActivityPub::TagManager.instance.uri_for(status),
+          atomUri: 'barbar',
         }
       end
 
-      before do
-        Fabricate(:status, reblog: status, account: sender, uri: 'bar')
+      context do
+        before do
+          Fabricate(:status, reblog: status, account: sender, uri: 'bar')
+        end
+
+        it 'deletes the reblog' do
+          subject.perform
+          expect(sender.reblogged?(status)).to be false
+        end
       end
 
-      it 'deletes the reblog' do
-        subject.perform
-        expect(sender.reblogged?(status)).to be false
+      context 'with atomUri' do
+        before do
+          Fabricate(:status, reblog: status, account: sender, uri: 'barbar')
+        end
+
+        it 'deletes the reblog by atomUri' do
+          subject.perform
+          expect(sender.reblogged?(status)).to be false
+        end
       end
     end