Evaluates the given expression and on success stores the result in
The `GType` of `value` will be the type given by [method@Gtk.Expression.get_value_type].
It is possible that expressions cannot be evaluated - for example when the expression references objects that have been destroyed or set to `NULL`. In that case `value` will remain empty and `FALSE` will be returned.
the this argument for the evaluation
an empty `GValue`
`TRUE` if the expression could be evaluated