Fix crash with intent-less actions

Follow-up to I00d46036a2cbb73f7f733fd35bf0b743a02807a1

Bug: 28818704
Change-Id: I9a444b9dd4cea92b4a770d7051c05c48818892ad

services/core/java/com/android/server/notification/NotificationManagerService.java

@@ -2582,6 +2582,9 @@ public class NotificationManagerService extends SystemService {
         }
         if (notification.actions != null) {
             for (Notification.Action action: notification.actions) {
+                if (action.actionIntent == null) {
+                    continue;
+                }
                 am.setPendingIntentWhitelistDuration(action.actionIntent.getTarget(), duration);
                 setPendingIntentWhitelistDuration(am, duration, action.getExtras());
                 final RemoteInput[] remoteInputs = action.getRemoteInputs();