Only apply top border to main graph

app/assets/javascripts/pipelines/components/graph/graph_component.vue

@@ -162,8 +162,10 @@ export default {
   <div class="js-pipeline-graph">
     <div
       ref="mainPipelineContainer"
-      class="gl-display-flex gl-position-relative gl-bg-gray-10 gl-white-space-nowrap gl-border-t-solid gl-border-t-1 gl-border-gray-100"
-      :class="{ 'gl-pipeline-min-h gl-py-5 gl-overflow-auto': !isLinkedPipeline }"
+      class="gl-display-flex gl-position-relative gl-bg-gray-10 gl-white-space-nowrap"
+      :class="{
+        'gl-pipeline-min-h gl-py-5 gl-overflow-auto gl-border-t-solid gl-border-t-1 gl-border-gray-100': !isLinkedPipeline,
+      }"
     >
       <linked-graph-wrapper>
         <template #upstream>