Make find_actual_head_pipeline private method

a

app/models/merge_request.rb

@@ -1300,11 +1300,6 @@ class MergeRequest < ActiveRecord::Base
       .find_by(sha: diff_base_sha)
   end
 
-  def find_actual_head_pipeline
-    source_project&.ci_pipelines
-                  &.latest_for_merge_request(self, source_branch, diff_head_sha)
-  end
-
   def discussions_rendered_on_frontend?
     true
   end
@@ -1348,4 +1343,11 @@ class MergeRequest < ActiveRecord::Base
 
     source_project.repository.squash_in_progress?(id)
   end
+
+  private
+
+  def find_actual_head_pipeline
+    source_project&.ci_pipelines
+                  &.latest_for_merge_request(self, source_branch, diff_head_sha)
+  end
 end