Fix size of mini pipeline to 24px in MR

app/assets/stylesheets/pages/merge_requests.scss

@@ -982,7 +982,14 @@ $mr-widget-min-height: 69px;
   }
 
   .mini-pipeline-graph-dropdown-toggle,
-  .stage-cell .mini-pipeline-graph-dropdown-toggle svg {
+  .stage-cell .mini-pipeline-graph-dropdown-toggle svg,
+  // As the `mini-pipeline-item` mixin specificity is lower
+  // than the toggle of dropdown with 'variant="link"' we add
+  // classes ".gl-button.btn-link" to make it more specific.
+  // Once FF ci_mini_pipeline_gl_dropdown is removed, the `mini-pipeline-item`
+  // itself could increase its specificity to simplify this selector
+  button.gl-button.btn-link.mini-pipeline-graph-gl-dropdown-toggle,
+  .stage-cell button.gl-button.btn-link.mini-pipeline-graph-gl-dropdown-toggle svg {
     height: $ci-action-icon-size-lg;
     width: $ci-action-icon-size-lg;
   }