Native spell checker isn't working

**Describe the bug**
The native spell checker isn't working, even with the wright config works

**To Reproduce**
Just set up the editor in a textarea with this config
```js
easyMDE({
element: document.getElementById("editor") as HTMLElement,
initialValue: props.use === "editor" ? props.post.content : "",
maxHeight: "300px",
spellChecker: false,
nativeSpellcheck: true,
});
```

**Expected behavior**
Spell checker working

**Version information**
Node: 20
Browser: Brave Latest, Firefox Nightly

Reproduce the issue with the provided EasyMDE configuration in Brave or Firefox, then trace how the nativeSpellcheck option is handled. The issue names no source file or test; done means native spell checking works in the textarea when nativeSpellcheck is enabled.

Written by the indexing model from the issue text.