Add correct C++ solver names for validation errors

[jtcooper10]

The C++ solvers use the wrong solver name when raising a SimulationError due to unsupported SBML features. To fix, the hard-coded name "SSACSolver" is substituted with the name property of the target solver.

Replicate by creating a model using one or more unsupported SBML objects:

import gillespy2

class TestModel(gillespy2.Model):
    def __init__(self):
        super().__init__(name="TestModel")
        self.add_species(gillespy2.Species(name="S", initial_value=0))
        self.add_assignment_rule(gillespy2.AssignmentRule(variable="S", formula="t"))
        self.add_function_definition(gillespy2.FunctionDefinition(name="f", function="x", args=["x"]))

# Raises an error, should now have the correct target name in error message
gillespy2.TauHybridCSolver(model=TestModel()).run()

Closes #698