Create settings screen for Notification Assistant

Test: this atest
Test: manual: change assistant and "adb shell dumpsys notification"
Test: manual: verify persistance through reboot (including none)

Fixes:120852765
Change-Id: Ie4516c3339246d66d7b6719ac5dd1d65c4d03b57
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index ae4ae2a..7565dd8 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -110,6 +110,7 @@
     public static class ZenModeEventRuleSettingsActivity extends SettingsActivity { /* empty */ }
     public static class SoundSettingsActivity extends SettingsActivity { /* empty */ }
     public static class ConfigureNotificationSettingsActivity extends SettingsActivity { /* empty */ }
+    public static class NotificationAssistantSettingsActivity extends SettingsActivity{ /* empty */ }
     public static class NotificationAppListActivity extends SettingsActivity { /* empty */ }
     public static class AppNotificationSettingsActivity extends SettingsActivity { /* empty */ }
     public static class ChannelNotificationSettingsActivity extends SettingsActivity { /* empty */ }