fix: resolve UpdateInternalArticleRequest duplicate declaration

Override the PUT /internal_articles/{id} endpoint in unstable API to use
a unique request name (UpdateInternalArticleBodyRequest) to avoid
conflicts with auto-generated type names.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: marcmlc

fern/unstable-openapi-overrides.yml

@@ -95,6 +95,12 @@ paths:
         - customChannelEvents
       x-fern-sdk-method-name: notifyQuickReplySelected
       x-fern-request-name: NotifyQuickReplySelectedRequest
+  '/internal_articles/{id}':
+    put:
+      x-fern-sdk-group-name:
+        - internalArticles
+      x-fern-sdk-method-name: update
+      x-fern-request-name: UpdateInternalArticleBodyRequest
 
 components:
   schemas: