Further cleanup of Span::test_data usage + span fixes (#7595)

# Description

Inspired by #7592

For brevity use `Value::test_{string,int,float,bool}`

Includes fixes to commands that were abusing `Span::test_data` in their
implementation. Now the call span is used where possible or the explicit
`Span::unknonw` is used.

## Command fixes
- Fix abuse of `Span::test_data()` in `query_xml`
- Fix abuse of `Span::test_data()` in `term size`
- Fix abuse of `Span::test_data()` in `seq date`
- Fix two abuses of `Span::test_data` in `nu-cli`
- Change `Span::test_data` to `Span::unknown` in `keybindings listen`
- Add proper call span to `registry query`
- Fix span use in `nu_plugin_query`
- Fix span assignment in `select`
- Use `Span::unknown` instead of `test_data` in more places

## Other
- Use `Value::test_int`/`test_float()` consistently
- More `test_string` and `test_bool`
- Fix unused imports


# User-Facing Changes

Some commands may now provide more helpful spans for downstream use in
errors

crates/nu-command/src/platform/dir_info.rs

@@ -255,13 +255,13 @@ impl From<FileInfo> for Value {
         });
 
         cols.push("directories".into());
-        vals.push(Value::nothing(Span::test_data()));
+        vals.push(Value::nothing(Span::unknown()));
 
         cols.push("files".into());
-        vals.push(Value::nothing(Span::test_data()));
+        vals.push(Value::nothing(Span::unknown()));
 
         // cols.push("errors".into());
-        // vals.push(Value::nothing(Span::test_data()));
+        // vals.push(Value::nothing(Span::unknown()));
 
         Value::Record {
             cols,