Merge branch '23849-pipeline-graph-bug' into 'master'

Only remove right connector of first build of last stage

Only remove right connector of first build of last stage.
Closes #23849

See merge request !7179

app/assets/stylesheets/pages/pipelines.scss

@@ -573,8 +573,7 @@
     .build {
       // Remove right connecting horizontal line from first build in last stage
       &:first-child {
-        &::after,
-        &::before {
+        &::after {
           border: none;
         }
       }