Fix #15440 default --empty fails at empty streams (#15562)

Fixes #15440 

# Description
Wraps ListStream stream type from `impl Iterator` to `Peekable<impl
Iterator>`, this allows checking for empty streams and treating them as
empty values
 
Example:
```
# previously
$ glob ? | default -e void
> # empty list

$ echo '' | default -e void
> void

####################

# now
$ glob ? | default -e void
> void

$ echo '' | default -e void
> void
```

# User-Facing Changes

empty list streams will behave as `nothing` values when testing for
emptiness

# Tests + Formatting

- Add 2 tests
- clippy OK
- fmt OK

# After Submitting

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

@@ -1,4 +1,4 @@
-use nu_test_support::{nu, pipeline};
+use nu_test_support::{fs::Stub::EmptyFile, nu, pipeline, playground::Playground};
 
 #[test]
 fn adds_row_data_if_column_missing() {
@@ -112,3 +112,41 @@ fn do_not_replace_empty_record() {
     let actual = nu!(r#"{} | default {a:5} | columns | length"#);
     assert_eq!(actual.out, "0");
 }
+
+#[test]
+fn replace_empty_list_stream() {
+    // This is specific for testing ListStreams when empty behave like other empty values
+    Playground::setup("glob_empty_list", |dirs, sandbox| {
+        sandbox.with_files(&[
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jttxt"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "glob ? | default -e void",
+        );
+
+        assert_eq!(actual.out, "void");
+    })
+}
+
+#[test]
+fn do_not_replace_non_empty_list_stream() {
+    // This is specific for testing ListStreams when empty behave like other empty values
+    Playground::setup("glob_non_empty_list", |dirs, sandbox| {
+        sandbox.with_files(&[
+            EmptyFile("yehuda.txt"),
+            EmptyFile("jt.rs"),
+            EmptyFile("andres.txt"),
+        ]);
+
+        let actual = nu!(
+            cwd: dirs.test(),
+            "glob '*.txt' | default -e void | length",
+        );
+
+        assert_eq!(actual.out, "2");
+    })
+}