Resolve "Geo: Optimize replication of project repo keep around refs"

What does this MR do and why?

This MR avoids triggering Repositories::KeepAroundRefsCreatedEvent event on keep_around method when no SHAs are passed. If there are no SHAs then there is no write_ref call: https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/git/keep_around.rb#L21-32

How to set up and validate locally

1. In the secondary site, tail geo.log
2. Comment on an issue.
3. Observe logs, there shouldn't be any log like the following one: {"severity":"INFO","time":"2022-05-19T00:50:32.648Z","correlation_id":null,"pid":50126,"host":"127.0.0.1","class":"Gitlab::Geo::LogCursor::Daemon","message":"Repository update","project_id":6,"source":"repository","resync_repository":true,"resync_wiki":false,"scheduled_at":"2022-05-18T17:50:32.629-07:00","replicable_project":true,"job_id":"d7d2a28e31b6840ff61a69fe","event_id":2,"cursor_delay_s":0.51}

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #362851 (closed)

ee/app/models/ee/repository.rb

@@ -60,14 +60,18 @@ def up_to_date_with_upstream?(branch_name)
     def keep_around(*shas)
       super
     ensure
-      # The keep_around method is called from different places. One of them
-      # is when a pipeline is created. So, in this case, it is still under
-      # Ci::Pipeline.transaction. It's safe to skip the transaction check
-      # because we already wrote the refs to the repository on disk.
-      Sidekiq::Worker.skipping_transaction_check do
-        ::Gitlab::EventStore.publish(
-          ::Repositories::KeepAroundRefsCreatedEvent.new(data: { project_id: project.id })
-        )
+      # If there are no SHAs received then there is no write_ref executed.
+      # The following condition avoids to publish unnecessary events.
+      if shas.compact.any?
+        # The keep_around method is called from different places. One of them
+        # is when a pipeline is created. So, in this case, it is still under
+        # Ci::Pipeline.transaction. It's safe to skip the transaction check
+        # because we already wrote the refs to the repository on disk.
+        Sidekiq::Worker.skipping_transaction_check do
+          ::Gitlab::EventStore.publish(
+            ::Repositories::KeepAroundRefsCreatedEvent.new(data: { project_id: project.id })
+          )
+        end
       end
     end