Throws an exception on enter.
### Version

```
moe v0.3.0

Git hash: 89542793bbfed27e338a9fbdb1b0a415db90875f
Build type: Release
```

### Environment

Terminal : `alacritty`, using a [startship](https://starship.rs/) ran tests with and without `starship`, same result.
Tried with `konsole`, same result.

Running `X` display.

`uname -a` -> `Linux archlinux 6.7.6-arch1-1 #1 SMP PREEMPT_DYNAMIC Fri, 23 Feb 2024 16:31:48 +0000 x86_64 GNU/Linux`

As per the moe requirements:
`extra/xclip 0.13-4`
`extra/xsel 1.2.1-1`
`core/ncurses 6.4_20230520-1`
`extra/nim 2.0.2-1`

### Category

Major — The software does not fulfill the task it is designed for.

### Steps to Reproduce

1. Startup `moe`
2. Click the `a` key once to enter insert/add mode.
3. Click `a` button a second time in order to write out an `a` sign on the screen.
4. Click enter.

### Detailed Description

The same error message (maybe for different reasons) can be seen in [this comment](https://github.com/fox0430/moe/issues/1881#issuecomment-1767056466).

`options.nim(230) get Error: unhandled exception: Can't obtain a value from a 'none' [UnpackDefect]`

![image](https://github.com/fox0430/moe/assets/32035685/e4431ae6-0b18-456b-b597-14aa55d4ac43)
