Fix inconsistency in ls sort-order (#13875)

Fixes #13267 

As we can see from the bisect done in the comments.
Bisected to https://github.com/nushell/nushell/pull/12625 /
460a1c8f87

We can see that this update brought the use of `read_dir` and for it, it
is mentioned in the [rust
docs](https://doc.rust-lang.org/std/fs/fn.read_dir.html#platform-specific-behavior)
that it does **not** provide any specific order of files.
As was the advice there, I went and applied a manual `sort` to the
entries and tested it manually on my local machine.

If required I could probably try and add tests for the order
consistency, would need some time to find my way around them, so I'm
sending the PR first.

crates/nu-command/tests/commands/ls.rs

@@ -833,3 +833,27 @@ fn list_symlink_with_full_path() {
         );
     })
 }
+
+#[test]
+fn consistent_list_order() {
+    Playground::setup("ls_test_order", |dirs, sandbox| {
+        sandbox.with_files(&[
+            EmptyFile("los.txt"),
+            EmptyFile("tres.txt"),
+            EmptyFile("amigos.txt"),
+            EmptyFile("arepas.clu"),
+        ]);
+
+        let no_arg = nu!(
+            cwd: dirs.test(), pipeline(
+            "ls"
+        ));
+
+        let with_arg = nu!(
+            cwd: dirs.test(), pipeline(
+            "ls ."
+        ));
+
+        assert_eq!(no_arg.out, with_arg.out);
+    })
+}