The model and the scene environment used to render material previews
can now be selected via buttons next to the preview in material editor.
Task-number: QDS-7347
Change-Id: I03089029e8420f80ed65be1c7b7a1ce4581f2fd4
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>