The modal to create root object suggest all the entities of a domain model instead of root entities

[gcoutable]

Steps to reproduce

1. Define a basic studio with one root element containing at least one child entity
2. Create a project instance
3. Create an empty model
4. Display the modal to create a new root object
5. Select the domain URI
6. Verify that Show only suggested root type is checked
7. Display the object type select options

Actual behavior

On the new architecture, the root element and the child entity are displayed like when Show only suggested root type is unchecked.

Expected behavior

On the new architecture, only the root element should be displayed

[gcoutable]

In the old architecture the work to find root element was delegated to the compatibility layer. In the new architecture, ISuggestedRootObjectTypesProvider does not have implementation. To fix this copy the code from Sirius desktop that does the work.