gptel: Clear reasoning field in multi-turn request

* gptel.el (gptel--handle-wait): Clear the reasoning field from
INFO when firing a request.  This field may be populated in a
multi-turn request, such as when using tool-calls with a reasoning
model. (#743)

Author: karthink

gptel.el

@@ -1979,7 +1979,7 @@ buffer."
   ;; a second network request: gptel tests for the presence of these flags to
   ;; handle state transitions.  (NOTE: Don't add :token to this.)
   (let ((info (gptel-fsm-info fsm)))
-    (dolist (key '(:tool-success :tool-use :error :http-status))
+    (dolist (key '(:tool-success :tool-use :error :http-status :reasoning))
       (when (plist-get info key)
         (plist-put info key nil))))
   (funcall