[User Feedback] unclear how to get counts from pub data

[javabster]

We got some user feedback that essentially points to the fact that the architecture for storing PubResults inside of PrimitiveResults and trying to access specific data isn't very intuitive. One suggestion for how we could make this more clear is that we could add a diagram showing how the properties are connected to each other on the primitive input/output page: https://docs.quantum.ibm.com/guides/primitive-input-output#sampler-output.

@kaelynj suggests something like this, but other options can be explored by whoever picks this ticket up:

└── PrimitiveResult/
    ├── PubResult[0]/
    │   ├── metadata
    │   └── data/
    │       ├── NAME_OF_REGISTER/
    │       │   └── BitArray of count data
    │       └── NAME_OF_ANOTHER_REGISTER/
    │           └── BitArray of count data
    └── PubResult[1]/
        ├── metadata
        └── data/
            └── NAME_OF_REGISTER/
                └── BitArray of count data for second pub

[kaelynj]

There is also some work happening to update the guides on how to best use BitArray objects in #2612