Masking with subcatch in grid

[hboisgon]

HydroMT-Wflow version checks

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• I have checked that this bug exists on the latest version of HydroMT-Wflow.

Reproducible Example

Run the test_model_methods.py::test_setup_lulc_vector and examine the example_wflow_model after calling the setup method.

Current behaviour

Not a real bug but currently masking of variables in grid with the basin boundaries happens in write_grid rather then in the setup_ methods. I think it would be better if it hapened during the set_grid method so that we have a more conform model in python and not only after/when writting.

Desired behaviour

See above.

Additional context

No response