properly convert env for buffer editor (#11636)

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# Description

environment variables were not correctly passed to `buffer_editor`.
Previously the conversion (if you can call it that) is incorrectly done
by `.as_string()`, which works for the most part, but ignores important
things like `PATH`, which are not strings in value form by default

(this issue was introduced in #10269, merged in #10535)

# User-Facing Changes
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crates/nu-cli/src/repl.rs

@@ -11,7 +11,7 @@ use miette::{ErrReport, IntoDiagnostic, Result};
 use nu_cmd_base::util::get_guaranteed_cwd;
 use nu_cmd_base::{hook::eval_hook, util::get_editor};
 use nu_color_config::StyleComputer;
-use nu_engine::convert_env_values;
+use nu_engine::{convert_env_values, env_to_strings};
 use nu_parser::{lex, parse, trim_quotes_str};
 use nu_protocol::{
     config::NuCursorShape,
@@ -300,12 +300,9 @@ pub fn evaluate_repl(
 
         line_editor = if let Ok((cmd, args)) = buffer_editor {
             let mut command = std::process::Command::new(&cmd);
-            command.args(args).envs(
-                engine_state
-                    .render_env_vars()
-                    .into_iter()
-                    .filter_map(|(k, v)| v.as_string().ok().map(|v| (k, v))),
-            );
+            command
+                .args(args)
+                .envs(env_to_strings(engine_state, stack)?);
             line_editor.with_buffer_editor(command, temp_file.clone())
         } else {
             line_editor