TypedArray<T> operator [] returning Variant makes little sence.

### Godot version

4.2

### godot-cpp version

4.2

### System information

Win 10

### Issue description

When using TypedArray I think the one would expect that accessing entries with operator [] will return you variable of type T. Instead it returns Variant, which is loosing all point to use TypedArray in first place.

This should give compilation error:
```
TypedArray a;
Dictionaty d = a[0];
```
As well as this construction is a bit annoying:
```
TypedArray a;
Node* n = (Node*) (Object*) a[0]; //beacuse varinat can only be cast to Object*
```

### Steps to reproduce

-

### Minimal reproduction project

-