Add androidx package to exemption

Change-Id: I0377d9e479ab876a316f2515716e83e8872aaaa6
Test: presubmit
Bug: 275494853
diff --git a/tests/tests/security/src/android/security/cts/PackageSignatureTest.java b/tests/tests/security/src/android/security/cts/PackageSignatureTest.java
index b6ee6ed..1f65973 100644
--- a/tests/tests/security/src/android/security/cts/PackageSignatureTest.java
+++ b/tests/tests/security/src/android/security/cts/PackageSignatureTest.java
@@ -127,6 +127,7 @@
             // Test utilities used by Tradefed harness
             "com.android.tradefed.utils.wifi",
             "android.tradefed.contentprovider",
+            "androidx.test.services",
 
             // Game used for CTS testing...
             "com.replica.replicaisland",