docs: replace legacy line‑dot‑left‑horizontal icons with unified dot icon across docs

apps/docs/content/(03-hierarchical)/tree-bfs/199-binary-tree-right-side-view.mdx

@@ -1,7 +1,7 @@
 ---
 title: '199. Binary Tree Right Side View'
 description: Given the root of a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom
-icon: line-dot-left-horizontal
+icon: dot
 sidebar:
   label: 'Binary Tree Right Side View'
   badge: 'Medium'