fix(poly): changed lambda from fespace to scalar

previously I had a lagrangian multipliers at every element; however, we are enforcing a global constraint so there need only be one lagrangian multiplier

src/poly/solver/public/polySolver.h

@@ -20,7 +20,6 @@ private:
     std::unique_ptr<mfem::H1_FECollection> feCollection;
 
     std::unique_ptr<mfem::FiniteElementSpace> feSpace;
-    std::unique_ptr<mfem::FiniteElementSpace> lambdaFeSpace;
 
     std::unique_ptr<polyMFEMUtils::CompositeNonlinearIntegrator> compositeIntegrator;