build(deps): remove @discordjs/rest undici patch

- Drop the patchedDependencies entry from package.json and bun.lock
- Delete patches/@discordjs%2Frest@2.6.1.patch, which pinned undici to 6.27.0

package.json

@@ -287,8 +287,5 @@
     "printWidth": 100,
     "singleQuote": true,
     "trailingComma": "all"
-  },
-  "patchedDependencies": {
-    "@discordjs/rest@2.6.1": "patches/@discordjs%2Frest@2.6.1.patch"
   }
 }