to json -r not removing whitespaces fix (#11948)

fixes #11900  

# Description
Use `serde_json` instead.

# User-Facing Changes
The problem described in the issue now no longer persists.

No whitespace in the output of `to json --raw`
Output of unicode escape changed to consistent `\uffff`

# Tests + Formatting
I corrected all Tests that were affected by this change.

tests/shell/pipeline/commands/internal.rs

@@ -607,7 +607,7 @@ fn index_row() {
         let foo = [[name]; [joe] [bob]]; echo $foo.1 | to json --raw
         ");
 
-    assert_eq!(actual.out, r#"{"name": "bob"}"#);
+    assert_eq!(actual.out, r#"{"name":"bob"}"#);
 }
 
 #[test]