NightLight: check if wlsunset exists, else dont enable NightLight

SystemMonitorSettings: If RAM usage is not toggled, don't show % option
Settings: remove NightLight from default bar widgets

Modules/Bar/Widgets/NightLight.qml

@@ -24,6 +24,12 @@ NIconButton {
   icon: Settings.data.nightLight.enabled ? (Settings.data.nightLight.forced ? "nightlight-forced" : "nightlight-on") : "nightlight-off"
   tooltipText: Settings.data.nightLight.enabled ? (Settings.data.nightLight.forced ? I18n.tr("tooltips.night-light-forced") : I18n.tr("tooltips.night-light-enabled")) : I18n.tr("tooltips.night-light-disabled")
   onClicked: {
+    // Check if wlsunset is available before enabling night light
+    if (!ProgramCheckerService.wlsunsetAvailable) {
+      ToastService.showWarning(I18n.tr("settings.display.night-light.section.label"), I18n.tr("toast.night-light.not-installed"))
+      return
+    }
+
     if (!Settings.data.nightLight.enabled) {
       Settings.data.nightLight.enabled = true
       Settings.data.nightLight.forced = false

Modules/Settings/Bar/WidgetSettings/SystemMonitorSettings.qml

@@ -62,6 +62,7 @@ ColumnLayout {
     label: I18n.tr("bar.widget-settings.system-monitor.memory-percentage")
     checked: valueShowMemoryAsPercent
     onToggled: checked => valueShowMemoryAsPercent = checked
+    visible: valueShowMemoryUsage
   }
 
   NToggle {