If not showing subscription item values in Model Browser, make final attempt to resolve Variable through experiment context

If current values are shown for subscription items in Model Browser labeling, things look like this:

However, if subscription item values are not shown, this can/will happen for "UC structures or purely solver-side Variable resolution:

This happens because the variable can only be resolved using the experiment context Variable, not the configuration context Variable because the referenced variable does not exist in the configuration context at all. Why experiment context is not always used is an optimization. Resolving through the configuration context is faster than using the experiment context.