Fix incorrect handling of boolean flags for builtin commands (#11492)

# Description
Possible fix of #11456
This PR fixes a bug where builtin commands did not respect the logic of
dynamically passed boolean flags. The reason is
[has_flag](6f59abaf43/crates/nu-protocol/src/ast/call.rs (L204C5-L212C6))
method did not evaluate and take into consideration expression used with
flag.

To address this issue a solution is proposed:
1. `has_flag` method is moved to `CallExt` and new logic to evaluate
expression and check if it is a boolean value is added
2. `has_flag_const` method is added to `CallExt` which is a constant
version of `has_flag`
3. `has_named` method is added to `Call` which is basically the old
logic of `has_flag`
4. All usages of `has_flag` in code are updated, mostly to pass
`engine_state` and `stack` to new `has_flag`. In `run_const` commands it
is replaced with `has_flag_const`. And in a few select places: parser,
`to nuon` and `into string` old logic via `has_named` is used.

# User-Facing Changes
Explicit values of boolean flags are now respected in builtin commands.
Before:

![image](https://github.com/nushell/nushell/assets/17511668/f9fbabb2-3cfd-43f9-ba9e-ece76d80043c)
After:

![image](https://github.com/nushell/nushell/assets/17511668/21867596-2075-437f-9c85-45563ac70083)

Another example:
Before:

![image](https://github.com/nushell/nushell/assets/17511668/efdbc5ca-5227-45a4-ac5b-532cdc2bbf5f)
After:

![image](https://github.com/nushell/nushell/assets/17511668/2907d5c5-aa93-404d-af1c-21cdc3d44646)


# Tests + Formatting
Added test reproducing some variants of original issue.

crates/nu-command/src/formats/to/csv.rs

@@ -67,7 +67,7 @@ impl Command for ToCsv {
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let head = call.head;
-        let noheaders = call.has_flag("noheaders");
+        let noheaders = call.has_flag(engine_state, stack, "noheaders")?;
         let separator: Option<Spanned<String>> = call.get_flag(engine_state, stack, "separator")?;
         let config = engine_state.get_config();
         to_csv(input, noheaders, separator, head, config)

crates/nu-command/src/formats/to/json.rs

@@ -44,8 +44,8 @@ impl Command for ToJson {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let raw = call.has_flag("raw");
-        let use_tabs = call.has_flag("tabs");
+        let raw = call.has_flag(engine_state, stack, "raw")?;
+        let use_tabs = call.has_flag(engine_state, stack, "tabs")?;
 
         let span = call.head;
         // allow ranges to expand and turn into array

crates/nu-command/src/formats/to/md.rs

@@ -1,5 +1,6 @@
 use indexmap::map::IndexMap;
 use nu_cmd_base::formats::to::delimited::merge_descriptors;
+use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
@@ -67,13 +68,13 @@ impl Command for ToMd {
     fn run(
         &self,
         engine_state: &EngineState,
-        _stack: &mut Stack,
+        stack: &mut Stack,
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let head = call.head;
-        let pretty = call.has_flag("pretty");
-        let per_element = call.has_flag("per-element");
+        let pretty = call.has_flag(engine_state, stack, "pretty")?;
+        let per_element = call.has_flag(engine_state, stack, "per-element")?;
         let config = engine_state.get_config();
         to_md(input, pretty, per_element, config, head)
     }

crates/nu-command/src/formats/to/nuon.rs

@@ -53,20 +53,18 @@ impl Command for ToNuon {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let raw = call.has_flag("raw");
-        let use_tabs = call.has_flag("tabs");
-        let use_indent = call.has_flag("indent");
+        let raw = call.has_flag(engine_state, stack, "raw")?;
+        let tabs: Option<usize> = call.get_flag(engine_state, stack, "tabs")?;
+        let indent: Option<usize> = call.get_flag(engine_state, stack, "indent")?;
 
         let span = call.head;
         let value = input.into_value(span);
 
         let nuon_result = if raw {
             value_to_string(&value, span, 0, None)
-        } else if use_tabs {
-            let tab_count: usize = call.get_flag(engine_state, stack, "tabs")?.unwrap_or(1);
+        } else if let Some(tab_count) = tabs {
             value_to_string(&value, span, 0, Some(&"\t".repeat(tab_count)))
-        } else if use_indent {
-            let indent: usize = call.get_flag(engine_state, stack, "indent")?.unwrap_or(2);
+        } else if let Some(indent) = indent {
             value_to_string(&value, span, 0, Some(&" ".repeat(indent)))
         } else {
             value_to_string(&value, span, 0, None)

crates/nu-command/src/formats/to/tsv.rs

@@ -1,4 +1,5 @@
 use crate::formats::to::delimited::to_delimited_data;
+use nu_engine::CallExt;
 use nu_protocol::ast::Call;
 use nu_protocol::engine::{Command, EngineState, Stack};
 use nu_protocol::{
@@ -49,12 +50,12 @@ impl Command for ToTsv {
     fn run(
         &self,
         engine_state: &EngineState,
-        _stack: &mut Stack,
+        stack: &mut Stack,
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let head = call.head;
-        let noheaders = call.has_flag("noheaders");
+        let noheaders = call.has_flag(engine_state, stack, "noheaders")?;
         let config = engine_state.get_config();
         to_tsv(input, noheaders, head, config)
     }