MapModel is missing set_row_data() function

[aamer-shaikh]

The C++ classes of SortModel, FilterModel, VectorModel, all have set_row_data() implemented.
However, MapModel is missing the same.

So if we try to update any item from UI, we get the warning -
Model::set_row_data was called on a read-only model

[tronical]

This is not possible with the current API. Suppose that you have a map model that converts from your own C++ data structure Foo to a slint_interpreter::Value: If set_row_data is called with a slint_interpreter::Value, MapModel canot know how to convert it back to Foo.

So this would require new API where the user also provides a function that maps the other way around, a bi-directional map model.