Add API access atom for protected signals

Bug: 322359767
Test: None
Change-Id: Ia2181f935b7d763759fa1dac266f7ca06a8b1b0f
diff --git a/stats/enums/adservices/common/adservices_enums.proto b/stats/enums/adservices/common/adservices_enums.proto
index 1298826..cafa2fd 100644
--- a/stats/enums/adservices/common/adservices_enums.proto
+++ b/stats/enums/adservices/common/adservices_enums.proto
@@ -469,6 +469,7 @@
   API_ACCESS_TYPE_TOPICS = 1;
   API_ACCESS_TYPE_CUSTOM_AUDIENCES = 2;
   API_ACCESS_TYPE_ATTRIBUTION = 3;
+  API_ACCESS_TYPE_PROTECTED_SIGNALS = 4;
 }
 
 /* Result of a call to check if an app allows access to a given AdServices API. */