Use generic token check in order to support Github Apps (#8048)

Co-authored-by: Rohit Malhotra <rohitvinodmalhotra@gmail.com>

openhands/integrations/github/github_service.py

@@ -120,6 +120,12 @@ class GitHubService(BaseGitService, GitService):
             email=response.get('email'),
         )
 
+    async def verify_access(self) -> bool:
+        """Verify if the token is valid by making a simple request."""
+        url = f'{self.BASE_URL}'
+        await self._make_request(url)
+        return True
+
     async def _fetch_paginated_repos(
         self, url: str, params: dict, max_repos: int, extract_key: str | None = None
     ) -> list[dict]: