Add "preselectedOptionValue" property for Dropdown/Radiobuttton/Checkboxes etc.

### Description

For many Apps, a dropdown with Country is used. It would be nice to have a way to preselect a country, without having to specify the index as some language differences might affect which index a country is at.

It would therefore be nice to have a property to these components stating which `AppOption.Value` should be preselected.

### Additional Information

_No response_

Start by locating the Dropdown, Radiobutton, and Checkbox components and tracing how they consume AppOption.Value. Define the scope across the named components, then verify that a preselected option can be chosen by value rather than index and that existing selection behavior remains intact.

Written by the indexing model from the issue text.