Formalize EXTRA_SKIP_CALL_FILTERING as system API

As part of telecom mainline prep, resolve the hidden reference from wear
services to EXTRA_SKIP_CALL_FILTERING by promoting it to a system API.

Bug: 322518197
Bug: 311773409
Test: m Telecom
Test m wear-services-calling-bluetooth & atest
WearServicesRoboTests:HfpClientConnectionServiceTest & atest
WearServicesRobotTests:HfpClientConnectionTest

Change-Id: I47b3f2d6146309157c18246e0e131bab1021c726
diff --git a/telecomm/java/android/telecom/PhoneAccount.java b/telecomm/java/android/telecom/PhoneAccount.java
index b7706a9..ab6f427 100644
--- a/telecomm/java/android/telecom/PhoneAccount.java
+++ b/telecomm/java/android/telecom/PhoneAccount.java
@@ -190,6 +190,8 @@
      * this may be used to skip call filtering when it has already been performed on another device.
      * @hide
      */
+    @SystemApi
+    @FlaggedApi(com.android.server.telecom.flags.Flags.FLAG_TELECOM_RESOLVE_HIDDEN_DEPENDENCIES)
     public static final String EXTRA_SKIP_CALL_FILTERING =
         "android.telecom.extra.SKIP_CALL_FILTERING";