chore: rename rothko painting (#44203)

* chore: rename files

* chore: update codebase

* chore: missed one

* chore: use proper title case

curriculum/challenges/_meta/learn-the-css-box-model-by-building-a-rothko-painting/meta.json

@@ -1,8 +1,8 @@
 {
-  "name": "CSS Box Model",
+  "name": "Learn the CSS Box Model by Building a Rothko Painting",
   "isUpcomingChange": true,
   "usesMultifileEditor": true,
-  "dashedName": "css-box-model",
+  "dashedName": "learn-the-css-box-model-by-building-a-rothko-painting",
   "order": 12,
   "time": "5 hours",
   "template": "",