drop nth command supports spreadable arguments (#15897)

## ✅ Improve `drop nth` command to support spreadable arguments

### Summary

This PR updates the `drop nth` command to support **spreadable
arguments** in a way consistent with other commands like `which`,
enabling:

```nu
[1 2 3 4 5] | drop nth 0 2 4
```

### What's Changed

* **Previously**: only a single index or a single range was accepted as
the first argument, with rest arguments ignored for ranges.

* **Now**: the command accepts any combination of:

  * Integers: to drop individual rows
  * Ranges: to drop slices of rows
  * Unbounded ranges: like `3..`, to drop from index onward

Example:

```nu
[one two three four five six] | drop nth 0 2 4..5
# drops "one", "three", "five", and "six"
```

### Test 

Manual Test:

![nu-dron_n](https://github.com/user-attachments/assets/02f3988c-ac02-4245-967c-16a9604be406)


### Notes

As per feedback:

* We **only collect the list of indices** to drop, not the input stream.
* Unbounded ranges are handled by terminating the stream early.

Let me know if you'd like further changes

---------

Co-authored-by: Kumar Ujjawal <kumar.ujjawal@greenpista.com>
Co-authored-by: Kumar Ujjawal <kumarujjawal@Kumars-MacBook-Air.local>

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

@@ -135,3 +135,75 @@ fn more_columns_than_record_has() {
 
     assert_eq!(actual.out, "{}");
 }
+
+#[test]
+fn drop_single_index() {
+    let actual = nu!("echo 10..15 | drop nth 2 | to json --raw");
+    assert_eq!(actual.out, "[10,11,13,14,15]");
+}
+
+#[test]
+fn drop_multiple_indices() {
+    let actual = nu!("echo 0..10 | drop nth 1 3 | to json --raw");
+    assert_eq!(actual.out, "[0,2,4,5,6,7,8,9,10]");
+}
+
+#[test]
+fn drop_inclusive_range() {
+    let actual = nu!("echo 10..15 | drop nth (2..4) | to json --raw");
+    assert_eq!(actual.out, "[10,11,15]");
+}
+
+#[test]
+fn drop_exclusive_range() {
+    let actual = nu!("echo 10..15 | drop nth (2..<4) | to json --raw");
+    assert_eq!(actual.out, "[10,11,14,15]");
+}
+
+#[test]
+fn drop_unbounded_range() {
+    let actual = nu!("echo 0..5 | drop nth 3.. | to json --raw");
+    assert_eq!(actual.out, "[0,1,2]");
+}
+
+#[test]
+fn drop_multiple_ranges_including_unbounded() {
+    let actual = nu!(pipeline(
+        r#"
+        0..30
+        | drop nth 0..10 20..
+        | to json --raw
+        "#
+    ));
+
+    assert_eq!(actual.out, "[11,12,13,14,15,16,17,18,19]");
+}
+
+#[test]
+fn drop_combination_of_unbounded_range_and_single_index() {
+    let actual = nu!(pipeline(
+        r#"
+            echo 0..15
+            | drop nth 10.. 5
+            | to json --raw
+            "#
+    ));
+
+    assert_eq!(actual.out, "[0,1,2,3,4,6,7,8,9]");
+}
+
+#[test]
+fn drop_combination_of_two_unbounded_ranges() {
+    let actual = nu!(pipeline(
+        r#"
+            echo 0..150
+            | drop nth 0..100 999..
+            | to json --raw
+            "#
+    ));
+
+    let expected: Vec<u32> = (101..=150).collect();
+    let expected_json = serde_json::to_string(&expected).unwrap();
+
+    assert_eq!(actual.out, expected_json);
+}