Changing matrix dropdown/dynamic choices doesn't change choices in columns

[andrewtelnov]

We do not update column's choices on changing matrix choices property when cell questions use the default choices from matrix and do not have their own choices.

The following code will not update cells questions choices property and as result UI.

matrix.choices.push(new Survey.ItemValue("newItem"));
matrix.choices[0].value = "newValue";
matrix.choices[1].text= "my text";

We should change the cells questions choices immediately.