Concentration parameter must be created with CanBeVaried = false

[Yuri05]

At the moment it's not the case and Concentration parameter appears e.g. in the SensitivityAnalysis in MoBi and we have other side effects (e.g. when creating model C++ code in SimModel)

PK-Sim/src/PKSim.Core/Model/ParameterFactory.cs

Lines 239 to 248 in 99ce0a3

	public IParameter CreateConcentrationParameterIn(IFormulaCache formulaCache)
	{
	var parameter = CreateFor(CoreConstants.Parameters.CONCENTRATION, PKSimBuildingBlockType.Simulation);
	parameter.BuildMode = ParameterBuildMode.Local;
	parameter.Info.Visible = false;
	parameter.Formula = _formulaFactory.ConcentrationFormulaFor(formulaCache);
	parameter.Dimension = _dimensionRepository.MolarConcentration;
	parameter.DisplayUnit = _displayUnitRetriever.PreferredUnitFor(parameter);
	return parameter;
	}