Add long options for platform and random (#10776)

crates/nu-command/tests/commands/random/chars.rs

@@ -3,7 +3,7 @@ use nu_test_support::nu;
 #[test]
 fn generates_chars_of_specified_length() {
     let actual = nu!(r#"
-        random chars -l 15 | size | get chars
+        random chars --length 15 | size | get chars
         "#);
 
     let result = actual.out;