In a form dialog, switching locales also changes the values of non-i18ned fields, which is wrong.

To reproduce the issue on demo author:
1. Log in Demo author and open a tour for editing, e.g. https://demoauthor.magnolia-cms.com/.magnolia/admincentral#app:tours:detail;/magnolia-travels/Vietnam--Tradition-and-Today:edit
2. Switch authoring locale to "German"
3. Locate a non-i18ned field and change the value, e.g. Tour Operator = Something
4. Switch authoring locale to "English"
5. Edit the value of the same field again, e.g. Tour Operator = Lemonize
6. Again, switch authoring locale back to "German": the field's value is changes back to Something, which is wrong. Lemonize would be right.

Note that the last entered value is being stored when saving the form, which is correct.

It seems that the field's values are not properly synchronized for non-i18ned fields. I wasn't able to figure out in detail where the code breaks: I might be wrong but I think the underlying datasource property still contains the correct value after the info.magnolia.ui.vaadin.form.FormViewReduced.Listener#localeChanged event is fired. There must be some event occurring thereafter which changes the value incorrectly.