building validations programmatically from a parent model

This is more like a 🤔 , since I solved how to get around it. I tried very hard to tweak the demo twiddle to reproduce this, but it just keeps crashing for different reasons.

I have a data structure of `Text`s, and each `Text` has multiple `Entry`s [sic]. Now, since each `Text` has different requirements of its `Entry`s, the model has an array, `entryProperties`, that looks like, say, this:

```javascript
// inside a createRecord("text", {...
entryProperties: [ { name: "page", type: "number" }, {name: "speaker", type: "string" }]
```

These all get saved under the umbrella of `properties` in the `Entry` model, so a typical `Entry` will look something like this:

```javascript
{ id: "blah", name: "foo", properties: { page: 234, speaker: "narrator" }}
```

so *since* the validation scheme of an `Entry`'s `properties` object is set at the `Text` level, I can't write a fixed Validations file in `app/validations` or whatever. Here's where things get weird...

In the component setting up the form, this works fine:

```javascript
// inside a Component definition
get EntryValidations() {
return {
name: validatePresence(true),
"properties.page": validateNumber(true),
"properties.speaker": validatePresence(true)
};
}
```

And then even this works fine:

```javascript
// inside a Component definition
get EntryValidations() {
const validations = { name: validatePresence(true) };
[{name: "page", type: "number"}, {name: "speaker", type: "string"}].forEach( prop => {
if(prop.type === "number") {
validations[`properties.${prop.name}`] = validateNumber(true);
} else {
validations[`properties.${prop.name}`] = validatePresence(true);
}

return validations;
}
```

But *this* causes any number of problems, most notably that the "name" `` wouldn't even update when I type in it. Here I'm passing a `Text` in as `this.args.model`:

```javascript
// inside a Component definition
get EntryValidations() {
const validations = { name: validatePresence(true) };
this.args.model.entryProperties.forEach( prop => {
if(prop.type === "number") {
validations[`properties.${prop.name}`] = validateNumber(true);
} else {
validations[`properties.${prop.name}`] = validatePresence(true);
}

return validations;
}
```

In the console, the validations object would look identical to the previous examples, but it just caused chaos. No amount of `.toArray()` or `[ ...this.args.model.entryProperties]` inside the `get EntryValidations()` would fix it. Finally, on a lark, I tried this, and it worked:

```javascript
// inside a Component definition
entryProperties = this.args.model.entryProperties.toArray();
get EntryValidations() {
const validations = { name: validatePresence(true) };
this.entryProperties.forEach( prop => {
if(prop.type === "number") {
validations[`properties.${prop.name}`] = validateNumber(true);
} else {
validations[`properties.${prop.name}`] = validatePresence(true);
}

return validations;
}
```

All is good, but this seems like a weird hiccup?