Toolkit2: Proper handling of parameters to plotters

JM reports:

vers/0/plotters/0/parameters
 0.0855118    19:11:35     [mpp2r02c02s08]rank:0 info         exahype::plotters::Plotter::Plotter(...)                write snapshot to file ./reference_solution every 0.005 time units with first snapshot at 0. plotter type is probe::ascii. Plotter configuration=(solver no=0,plotter identifier (type)=probe::ascii,written unknowns=9,time=0,repeat=0.005,file name=./reference_solution,plotter parameters={"select":{"x":0.5,"y":0.5,"z":0.8}},device configured=0)
 0.085593     19:11:35     [mpp2r02c02s08]rank:0 error        exahype::plotters::ADERDG2ProbeAscii::init()            Probe location is invalid. Require x,y,z values. Have {"select":{"x":0.5,"y":0.5,"z":0.8}} (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./ExaHyPE/exahype/plotters/ADERDG2ProbeAscii.cpp,line:56)
 0.085651     19:11:35     [mpp2r02c02s08]rank:0 error        exahype::parser::Parser::getIntFromPath()               Missing entry /solvers/0/plotters/0/parameters/x ([json.exception.out_of_range.403] key 'x' not found) (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./ExaHyPE/exahype/parser/Parser.cpp,line:346)
 0.0856928    19:11:35     [mpp2r02c02s08]rank:0 error        exahype::parser::Parser::getIntFromPath()               Missing entry /solvers/0/plotters/0/parameters/y ([json.exception.out_of_range.403] key 'y' not found) (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./ExaHyPE/exahype/parser/Parser.cpp,line:346)
 0.0857256    19:11:35     [mpp2r02c02s08]rank:0 error        exahype::parser::Parser::getIntFromPath()               Missing entry /solvers/0/plotters/0/parameters/z ([json.exception.out_of_range.403] key 'z' not found) (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./ExaHyPE/exahype/parser/Parser.cpp,line:346)
 0.0879261    error        was not able to open input file exahype.log-filter (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./Peano/tarch/logging/LogFilterFileReader.cpp,line:88)
 0.0879611    warning      filter file exahype.log-filter was invalid. Switch on all log statements (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./Peano/tarch/logging/LogFilterFileReader.cpp,line:105)
 0.0879824    error        do not run code as parser reported errors (file:/home/hpc/pr63so/di57wuf/ExaHyPE-Engine/toolkit2-linear_flux_ncp_mm.exahype-build/./ExaHyPE/exahype/runners/Runner.cpp,line:691)
 0.0879934    info         quit with error code 1
status=COMPLETED

This does not seem to be a fault by the C++ Parser but maybe instead by the classic-exahype -> JSON converter in the toolkit.