Support POI.Optimizer(Package.Optimizer)

[odow]

Currently, we assume that we get an instantiated optimizer

ParametricOptInterface.jl/src/ParametricOptInterface.jl

Lines 175 to 176 in 87406b4

	function Optimizer(
	optimizer::OT;

we should also support the typical POI.Optimizer(HiGHS.Optimizer) that appropriately instantiates the inner optimizer.

This would avoid confusions like https://discourse.julialang.org/t/solver-attributes-and-set-optimizer-with-parametricoptinterface-jl-and-jump-jl/129935