fix(shortcuts): prevent horizontal scrollbar

Signed-off-by: Phil Kuang <pkuang@factset.com>

.changeset/brave-brooms-warn.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-shortcuts': patch
+---
+
+Fix horizontal scroll bar appearance issue

plugins/shortcuts/src/Shortcuts.tsx

@@ -26,7 +26,7 @@ import { shortcutsApiRef } from './api';
 const useStyles = makeStyles({
   root: {
     flex: '1 1 auto',
-    overflow: 'scroll',
+    overflowY: 'scroll',
   },
 });