respect a users locale with the right prompt (#10273)

# Description

This PR tries to respect a person's locale setting with date/time in the
default right prompt. This also restores the right prompt so that it
does not load from the US default from reedline.

closes https://github.com/nushell/nushell/issues/9924


Here's the fromat reference if anyone thinks there's a better time
format. I could be talked into `%c` maybe.
https://docs.rs/chrono/latest/chrono/format/strftime/index.html

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crates/nu-utils/src/sample_config/default_env.nu

@@ -22,7 +22,7 @@ def create_right_prompt [] {
     let time_segment = ([
         (ansi reset)
         (ansi magenta)
-        (date now | format date '%Y/%m/%d %r')
+        (date now | format date '%x %X %p') # try to respect user's locale
     ] | str join | str replace --regex --all "([/:])" $"(ansi green)${1}(ansi magenta)" |
         str replace --regex --all "([AP]M)" $"(ansi magenta_underline)${1}")
 
@@ -37,7 +37,8 @@ def create_right_prompt [] {
 
 # Use nushell functions to define your right and left prompt
 $env.PROMPT_COMMAND = {|| create_left_prompt }
-# $env.PROMPT_COMMAND_RIGHT = {|| create_right_prompt }
+# FIXME: This default is not implemented in rust code as of 2023-09-08.
+$env.PROMPT_COMMAND_RIGHT = {|| create_right_prompt }
 
 # The prompt indicators are environmental variables that represent
 # the state of the prompt