Only post 'Retry' message if Danger says anything

Signed-off-by: Rémy Coutable <remy@rymai.me>

Dangerfile

@@ -15,4 +15,8 @@ gitlab_danger.rule_names.each do |file|
   danger.import_dangerfile(path: File.join('danger', file))
 end
 
-markdown("**If needed, you can retry the [`danger-review` job](#{ENV['CI_JOB_URL']}) that generated this comment.**") if gitlab_danger.ci?
+anything_to_post = status_report.values.any? { |data| data.any? }
+
+if gitlab_danger.ci? && anything_to_post
+  markdown("**If needed, you can retry the [`danger-review` job](#{ENV['CI_JOB_URL']}) that generated this comment.**")
+end