[Notifications] Use Date.now() instead of new Date().getTime()

The former is slightly more efficient

applets/notifications/package/contents/ui/FullRepresentation.qml

@@ -204,7 +204,7 @@ PlasmaComponents3.Page {
                     var sections = [];
 
                     // Show until time if valid but not if too far int he future
-                    if (!isNaN(inhibitedUntil.getTime()) && inhibitedUntil.getTime() - new Date().getTime() < 100 * 24 * 60 * 60 * 1000 /* 1 year*/) {
+                    if (!isNaN(inhibitedUntil.getTime()) && inhibitedUntil.getTime() - Date.now() < 100 * 24 * 60 * 60 * 1000 /* 1 year*/) {
                         sections.push(i18nc("Do not disturb until date", "Until %1",
                                             KCoreAddons.Format.formatRelativeDateTime(inhibitedUntil, Locale.ShortFormat)));
                     }

applets/notifications/package/contents/ui/NotificationHeader.qml

@@ -120,8 +120,7 @@ RowLayout {
                 return "";
             }
 
-            var now = new Date();
-            var deltaMinutes = Math.floor((now.getTime() - time.getTime()) / 1000 / 60);
+            var deltaMinutes = Math.floor((Date.now() - time.getTime()) / 1000 / 60);
             if (deltaMinutes < 1) {
                 return "";
             }

applets/notifications/package/contents/ui/global/Globals.qml

@@ -256,7 +256,7 @@ QtObject {
 
             var inhibitedUntil = notificationSettings.notificationsInhibitedUntil;
             if (!isNaN(inhibitedUntil.getTime())) {
-                inhibited |= (new Date().getTime() < inhibitedUntil.getTime());
+                inhibited |= (Date.now() < inhibitedUntil.getTime());
             }
 
             if (notificationSettings.notificationsInhibitedByApplication) {

applets/notifications/package/contents/ui/main.qml

@@ -79,7 +79,7 @@ Item {
                 // Show until time if valid but not if too far in the future
                 // TODO check app inhibition, too
                 if (inhibitedUntilValid
-                        && inhibitedUntil.getTime() - new Date().getTime() < 100 * 24 * 60 * 60 * 1000 /* 100 days*/) {
+                        && inhibitedUntil.getTime() - Date.now() < 100 * 24 * 60 * 60 * 1000 /* 100 days*/) {
                         lines.push(i18n("Do not disturb until %1",
                                      KCoreAddons.Format.formatRelativeDateTime(inhibitedUntil, Locale.ShortFormat)));
                 } else {