Explicitly show ResultBuilder Node as part of execution in the UI

[skrawcz]

Is your feature request related to a problem? Please describe.
The result builder is technically part of the graph, but it isn't shown -- nor is its output. This can make it hard to see what a whole execution actually produced.

Describe the solution you'd like
The result builder node should show up under execution - along with the data observability, etc.

Describe alternatives you've considered
We already do this for materializers -- they are effectively have a result builder component.

Additional context
Would allow us to compare the output of two executions more easily.