Strange behavior with an array of objects

## VERSION
4.1.0

## Test Case
[Repo](https://github.com/AmauryD/ember-changeset-validations-bug-repro)
[The files](https://github.com/AmauryD/ember-changeset-validations-bug-repro/tree/main/app/components)

## Steps to reproduce

[In the test case]
1. Input some text in the comments
2. add some comments and some text
3. try to rollback

[In any changeset]
1. Have some array with objects inside of your changeset
2. Change the content of some objects in the array
3. Try to rollback/trigger validation

## Expected Behavior
The content of the object in the array also rollbacks.
Validation triggers properly for in-array object keys.

## Actual Behavior
The content of the objects in the array is not roll-backed after modification.
Impossible to make validation works for properties of nested objects. (except when a new object is added/deleted to the main array, but its not real-time for the properties of these objects)

Maybe i'm doing it the wrong way, i never saw support for this kind of structure and validation in ember-changeset, so let me know if it's a bug or just me !

Quick overview of the test case:
```js
const validator = {
title: [validatePresence(true)],
content: [validatePresence(true)],
comments: [
(e) => {
/**
* Validates only when array is changed
*/
console.log(e);
return true;
},
],
// not working
'comments.0.content': [
(e) => {
console.log(e);
return true;
},
],
};
...
Changeset({
title: 'Article',
comments: [
{
content: 'That was fun', <-- content does not validate when modified and does not rollback
},
{
content: 'That was not fun',
},
],
lookupValidator(validator),
validator
})
```