set cloudflare not_found_handling to look for our custom 404 page

see docs
https://docs.astro.build/en/guides/deploy/cloudflare/#404-behavior

Author: nbogie

wrangler.jsonc

@@ -17,7 +17,8 @@
     "nodejs_compat"
   ],
   "assets": {
-    "directory": "dist"
+    "directory": "dist",
+    "not_found_handling": "404-page"
   },
   "env": {
     "beta": {