Fix warnings and compile errors on nightly (#6886)

Nightly has added a bunch of compiler and linter warnings. There is also
two dependencies that fail compilation on latest nightly due to using
the old `stdsimd` feature name. This PR fixes them.

libs/utils/src/completion.rs

@@ -4,7 +4,9 @@ use tokio_util::task::{task_tracker::TaskTrackerToken, TaskTracker};
 ///
 /// Can be cloned, moved and kept around in futures as "guard objects".
 #[derive(Clone)]
-pub struct Completion(TaskTrackerToken);
+pub struct Completion {
+    _token: TaskTrackerToken,
+}
 
 /// Barrier will wait until all clones of [`Completion`] have been dropped.
 #[derive(Clone)]
@@ -49,5 +51,5 @@ pub fn channel() -> (Completion, Barrier) {
     tracker.close();
 
     let token = tracker.token();
-    (Completion(token), Barrier(tracker))
+    (Completion { _token: token }, Barrier(tracker))
 }