Return false when there are no findings

ee/app/models/vulnerability.rb

@@ -74,6 +74,8 @@ class Vulnerability < ApplicationRecord
   end
 
   def resolved_on_default_branch
+    return false unless findings.any?
+
     latest_successful_pipeline_for_default_branch = project.latest_successful_pipeline_for_default_branch
     latest_pipeline_with_vulnerability = finding.pipelines.order(created_at: :desc).first
     latest_pipeline_with_vulnerability != latest_successful_pipeline_for_default_branch