Remove "Wall of browser bugs" page. (#29297)

While important in the past, it has become obsolete, so removing it seems the best solution.

site/content/docs/4.3/migration.md

@@ -135,4 +135,8 @@ Badges were overhauled to better differentiate themselves from buttons and to be
 - **Todo:** Drop `.text-hide` as it's an antiquated method for hiding text that shouldn't be used anymore
 - **Todo:** Split utilities into property-value utility classes and helpers
 
+## Docs
+
+-  Removed "Wall of browser bugs" page because it has become obsolete
+
 ## Build tools