When the [old Endpoint](https://spec.matrix.org/v1.14/client-server-api/#get_matrixmediav3downloadservernamemediaid) cannot be downloaded, fall back to the [new endpoint](https://spec.matrix.org/v1.14/client-server-api/#get_matrixclientv1mediadownloadservernamemediaid).
Requires D216
Type: add