fix account_id property

botocore/credentials.py

@@ -449,16 +449,8 @@ def token(self, value):
 
     @property
     def account_id(self):
-        """Warning: Using this property can lead to race conditions if you
-        access another property subsequently along the refresh boundary.
-        Please use get_frozen_credentials instead.
-        """
-        self._refresh()
-        return self._account_id
-
-    @account_id.setter
-    def account_id(self, value):
-        self._account_id = value
+        frozen_credentials = self.get_frozen_credentials()
+        return frozen_credentials.account_id
 
     def _seconds_remaining(self):
         delta = self._expiry_time - self._time_fetcher()