User Defined Supports not Included in Expectations

[pulsipher]

This came up with updating https://github.com/zavalab/JuliaBox/blob/master/InfiniteDimensionalCases/CaseStudy1/stochastic_optimal_powerflow.jl. Since expectations look for using supports with the WeightedSample label for use with expectations with respect to random parameters, any user defined supports are ignored. This is problematic when the user provides sampled supports when defining the infinite parameter (e.g., they want multiple models to use the same supports), but these are labeled as UserDefined.