Validation of annotation controller: separation of concerns is disturbed

As we know from crash reports, a lot of unreproducible crashes occur near the "CreateAnnotationWidgetController" class.
We have found that its "validate" method not only validates the model but updates this model!

Addition of a simple feature UGENE-1255 leaded to a new crash after validating the model.

It is needed to remove updateModel call from the validate method.
Also, remove the temporary stub from the updateModel method:

if (model.annotationObjectRef.isValid()) { // TODO: remove this and updateModel call from validate
    return;
}