Add rule for new system service

Update policy for new system service, used for Apps to present the
toolbar UI.

Bug: 190030331
Bug: 205822301
Test: manual. Can boot to home and get manager successfully.

Change-Id: Iee88681a93ae272a90896ccd2a6b64c26c809e82
diff --git a/private/service_contexts b/private/service_contexts
index 327b4f7..c378aec 100644
--- a/private/service_contexts
+++ b/private/service_contexts
@@ -274,6 +274,7 @@
 search_ui                                 u:object_r:search_ui_service:s0
 secure_element                            u:object_r:secure_element_service:s0
 sec_key_att_app_id_provider               u:object_r:sec_key_att_app_id_provider_service:s0
+selection_toolbar                         u:object_r:selection_toolbar_service:s0
 sensorservice                             u:object_r:sensorservice_service:s0
 sensor_privacy                            u:object_r:sensor_privacy_service:s0
 serial                                    u:object_r:serial_service:s0