Rust-internal `color_config` value does not match `default_config.nu`

Describe the bug

My understanding is that the Rust-internal config values are supposed to match those in the default_config.nu (at least the one we have now - It will likely be changing to sample_config.nu in the near future).

But without a config file, the current setting is simply an empty record $env.config.color_config = {}.

This appears to be because, unlike other nu-protocol::config settings, there's no struct for color_config. Thus there are no defaults, and also (as noted in #8703), no checking of the keys.

How to reproduce

# No config files
nu -n
# Populate config with default values
$env.config = {}
$env.config.history                                                                                                                                                                                                         11/08/2024 09:41:47 AM
# => ╭───────────────┬───────────╮
# => │ max_size      │ 100000    │
# => │ sync_on_enter │ true      │
# => │ file_format   │ plaintext │
# => │ isolation     │ false     │
# => ╰───────────────┴───────────╯

$env.config.color_config
# => ╭──────────────╮
# => │ empty record │
# => ╰──────────────╯

$env.config.color_config.junk_value = 1
# => No error, no result

$env.config.history.junk_value = 1                                                                                                                                                                                          
# => Error: nu::shell::invalid_config

Expected behavior

Defaults values for each color_config key are populated. (And per #8703) Setting an invalid key results in an error.

Configuration

Compare default_config.nu with the nu-protocol::config settings and trace how config values are initialized when running nu -n. Reproduce the color_config and history assignments from the issue; done means color_config has matching defaults and assigning an unknown key produces an invalid_config error.