fix(telegram): use thread fallback helper in slash-confirm result send

PR #23458 introduced _send_message_with_thread_fallback() and applied it
to all control-style sends (send_update_prompt, send_approval_request,
send_model_picker_prompt), but the slash-confirm result message in
handle_callback_query still called self._bot.send_message directly.

In supergroups with stale message_thread_id on the callback's parent
message, this raises "Message thread not found" and silently swallows
the result text. Replace with the helper so the same retry-without-
thread-id logic applies.

gateway/platforms/telegram.py

@@ -2772,7 +2772,7 @@ class TelegramAdapter(BasePlatformAdapter):
                                     {"thread_id": str(thread_id)},
                                 )
                             )
-                        await self._bot.send_message(**send_kwargs)
+                        await self._send_message_with_thread_fallback(**send_kwargs)
                 except Exception as exc:
                     logger.error("[%s] slash-confirm callback failed: %s", self.name, exc, exc_info=True)
             return