Mark ACTION_VOICE_ASSIST as SystemApi

.. since it is implemented by a system app. This allows the
CTS test that verifies android.* namespace intents to pass.

Change-Id: I083e1d12a79fa67e15158ca7390353303cd0e06e
Fixes: 35274957
Test: cts-tradefed run cts-dev -m CtsSignatureTestCases
diff --git a/core/java/android/content/Intent.java b/core/java/android/content/Intent.java
index 870db217..e0dc10d 100644
--- a/core/java/android/content/Intent.java
+++ b/core/java/android/content/Intent.java
@@ -1324,6 +1324,7 @@
      * Output: nothing.
      * @hide
      */
+    @SystemApi
     @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
     public static final String ACTION_VOICE_ASSIST = "android.intent.action.VOICE_ASSIST";