Update PrescribedForce.cpp
Update PrescribedForce.cpp

Made `name` argument a `const` reference
opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core