Add incidentcompanion service.

It is a side channel for dumpstate and incidentd to communicate
status and get user authorization to share bugreports by calling
system_server.

Test: atest PermissionControllerTest / atest GooglePermissionControllerTest
Change-Id: I995a43a25f375e5c97dba1deb92ebe893ca8585d
diff --git a/private/service_contexts b/private/service_contexts
index 4ce5566..ba06542 100644
--- a/private/service_contexts
+++ b/private/service_contexts
@@ -75,6 +75,7 @@
 ions                                      u:object_r:radio_service:s0
 idmap                                     u:object_r:idmap_service:s0
 incident                                  u:object_r:incident_service:s0
+incidentcompanion                         u:object_r:incidentcompanion_service:s0
 inputflinger                              u:object_r:inputflinger_service:s0
 input_method                              u:object_r:input_method_service:s0
 input                                     u:object_r:input_service:s0