The example used to default to the Default style, and when that was
renamed to Basic and the default style behavior changed, we forgot to
adapt the style property in the QML Settings instance.
We should now not set any value as a default, and instead ensure that
the style is set on the QSettings in C++.
Pick-to: 6.1 6.0
Change-Id: Ia8654f28ae6adc9171d667c2c5c3603a15251cab
Fixes: QTBUG-91989
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
23cad8990c