feat: add message param and error responses to createTicket (#632)

## Summary
- Add `message` parameter to the `createTicket` endpoint request body
for OAuth ticket creation
- Add 401 (Unauthorized) and 422 (Unprocessable Entity) error response
schemas to `createTicket`
- Bump version to 2.51.0 to match release
- Rebuild Go client with updated models

## Test plan
- [ ] CI passes (`npm test` — lint, build, unit tests)
- [ ] Go client compiles with new models
- [ ] Verify `createTicket` endpoint accepts `message` in request body

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

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: biilmann

package-lock.json

@@ -1,7 +1,7 @@
 {
   "name": "@netlify/open-api",
   "description": "Netlify's open-api definition as a module",
-  "version": "2.50.0",
+  "version": "2.51.0",
   "author": "Netlify",
   "ava": {
     "files": [

package.json

@@ -1,6 +1,6 @@
 swagger: '2.0'
 info:
-  version: 2.50.0
+  version: 2.51.0
   title: Netlify's API documentation
   description: >-
     Netlify is a hosting service for the programmable web. It understands your