allow select to take a $variable with a list of columns (#9987)

# Description

This PR enables `select` to take a constructed list of columns as a
variable.

```nushell
> let cols = [name type];[[name type size]; [Cargo.toml toml 1kb] [Cargo.lock toml 2kb]] | select $cols
  ╭#┬───name───┬type╮
  │0│Cargo.toml│toml│
  │1│Cargo.lock│toml│
  ╰─┴──────────┴────╯
```
and rows
```nushell
> let rows = [0 2];[[name type size]; [Cargo.toml toml 1kb] [Cargo.lock toml 2kb] [file.json json 3kb]] | select $rows
  ╭#┬───name───┬type┬size╮
  │0│Cargo.toml│toml│1kb │
  │1│file.json │json│3kb │
  ╰─┴──────────┴────┴────╯
```

# User-Facing Changes
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crates/nu-command/tests/commands/select.rs

@@ -244,3 +244,23 @@ fn select_on_empty_list_returns_empty_list() {
     let actual = nu!("[] | each {|i| $i} | select foo | to nuon");
     assert_eq!(actual.out, "[]");
 }
+
+#[test]
+fn select_columns_with_variable_list() {
+    let actual = nu!(r#"
+        let columns = [a c];
+        echo [[a b c]; [1 2 3]] | select $columns | to nuon
+        "#);
+
+    assert_eq!(actual.out, "[[a, c]; [1, 3]]");
+}
+
+#[test]
+fn select_rows_with_variable_list() {
+    let actual = nu!(r#"
+        let rows = [0 2];
+        echo [[a b c]; [1 2 3] [4 5 6] [7 8 9]] | select $rows | to nuon
+        "#);
+
+    assert_eq!(actual.out, "[[a, b, c]; [1, 2, 3], [7, 8, 9]]");
+}