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

apps/docs/content/(04-relational)/graph-bfs/994-rotting-oranges.mdx

@@ -1,7 +1,7 @@
 ---
 title: '994. Rotting Oranges'
 description: 'You are given an m x n grid where each cell can have one of three values:'
-icon: line-dot-left-horizontal
+icon: dot
 sidebar:
   label: 'Rotting Oranges'
   badge: 'Medium'