Better handling for `LogicStructure`s in `Pipeline`s

### Motivation

Currently, when you `get` a signal in a `Pipeline`, it just references that signal and that's it. But what about `LogicStructure`s? If you access an element of a `LogicStructure` in additional to the `LogicStructure` itself, they are treated as separate signals. That's kind of confusing and unintuitive.

### Desired solution

Make `Pipeline` more `LogicStructure`-aware, treating a `get` on an element of a `LogicStructure` the same as getting the `LogicStructure` then accessing its element.

### Alternatives considered

_No response_

### Additional details

_No response_