adapted call of discretizations

src/coupled/solvers/SegregatedSolver.cpp

src/coupled/transfers/MultiPartTransfer.cpp

src/elasticity/assemble/IElasticity.cpp

src/elasticity/solvers/IterativePressureSolver.cpp

src/electrophysiology/assemble/Monodomain.cpp

src/electrophysiology/solvers/ElphySolver.cpp