refactor: import FD traits from std instead of rustix

Signed-off-by: Martin Kröning <martin.kroening@eonerc.rwth-aachen.de>

rosenpass/tests/api-integration-tests-api-setup.rs

@@ -23,7 +23,7 @@ use rosenpass_util::{
     mio::WriteWithFileDescriptors,
     zerocopy::ZerocopySliceExt,
 };
-use rustix::fd::{AsFd, AsRawFd};
+use std::os::fd::{AsFd, AsRawFd};
 use tempfile::TempDir;
 use zerocopy::AsBytes;