Function fxaclient_ffi::fxa_set_push_subscription

#[no_mangle]pub extern "C" fn fxa_set_push_subscription(
    handle: u64, 
    endpoint: FfiStr<'_>, 
    public_key: FfiStr<'_>, 
    auth_key: FfiStr<'_>, 
    error: &mut ExternError
)

Update the Push subscription information for the current device.