Qt: Don't store floats in settings as QVariant data

src/duckstation-qt/qtsettingsinterface.cpp

@@ -59,7 +59,7 @@ void QtSettingsInterface::SetIntValue(const char* section, const char* key, int
 
 void QtSettingsInterface::SetFloatValue(const char* section, const char* key, float value)
 {
-  m_settings.setValue(GetFullKey(section, key), QVariant(value));
+  m_settings.setValue(GetFullKey(section, key), QString::number(value));
 }
 
 void QtSettingsInterface::SetBoolValue(const char* section, const char* key, bool value)

src/duckstation-qt/settingwidgetbinder.h

@@ -172,7 +172,7 @@ void BindWidgetToNormalizedSetting(QtHostInterface* hi, WidgetType* widget, cons
 
   Accessor::connectValueChanged(widget, [hi, widget, setting_name, range]() {
     const float new_value = (static_cast<float>(Accessor::getIntValue(widget)) / range);
-    hi->putSettingValue(setting_name, new_value);
+    hi->putSettingValue(setting_name, QString::number(new_value));
     hi->applySettings();
   });
 }