Function authorize 

async fn authorize<'a, F, Fut>(
    polkit: Option<&'a PolkitAuthority>,
    check: F,
) -> Result<(), VarlinkWalldClientError>
where
    F: FnOnce(&'a PolkitAuthority) -> Fut,
    Fut: Future<Output = Result<bool>>,

Wrapper doing some basic error handling against a polkit check.