Make sure ApiResult is ready before using it

In core the ApiResult is not actually ready to
use until just before execute() is called.

For this reason we can no construct the resultBuilder
in the constructor but instead use method which is
in turn called from within execute()

Bug: 57531

Change-Id: Iec91a8b471738f0958d9e1432fcb9bbf228cf096
Merge "Make sure ApiResult is ready before using it"