Selection checkbox stays checked if beforeSelectionChange returns false

[arcady-zherdev]

Most probably is a Grid level issue but reproduced in the Gantt advanced demo. Steps:

1. modify assignment column like this:

new Gantt({
    columns : [
        {
            type : 'resourceassignment',
            width : 120,
            editor : {
                picker : {
                    listeners : {
                        beforeSelectionChange({ action, mode, selected }) {
                            // prevent assigning resource with id===7
                            return !selected.find(rec => rec.resourceId === 7)
                        }
                    },
                }
            }
        },
......

2. it prevent assigning resource Dan
3. but if you check it it stays checked even though not included into selection