Use pipeline.commit for code quality report links

Instead of pipeline.ref, which in the case of a merge request pipeline
refers to the merge request instead, leading to the wrong file URL

ee/app/views/projects/pipelines/_tabs_content.html.haml

@@ -30,4 +30,4 @@
 - if codequality_report_download_path
   #js-tab-codequality.tab-pane
     #js-pipeline-codequality-report{ data: { codequality_report_download_path: codequality_report_download_path,
-    blob_path: project_blob_path(project, pipeline.ref) } }
+    blob_path: project_blob_path(project, pipeline.commit) } }