onChange function becomes field in SchedulerPro ProjectModel

[jsakalos]

When we define onChange on ProjectModel like this:

    project : {
        autoLoad  : true,
        transport : {
            load : {
                url : 'data/data.json'
            }
        },
        onChange : () => {
            console.log('here we are');
        }

it will become a DataField on instantiation. That can cause the scheduler to crash such as here: #7454

[isglass]

ProjectModel should probably not autoExpose fields