Add @TestApi to Context.updateDeviceId

CTS tests have already been added in DeviceAssociationTest, but
that CL missed adding the annotation in the method.

This method, even if @hide, is necessary for key framework
behaviors to allow for implicit device associations to work well.

Bug: 266091657
Test: atest DeviceAssociationTest
Change-Id: I171b14379a21f88f3111206e665c8af41a6957e0

core/api/test-current.txt

@@ -758,6 +758,7 @@ package android.content {
     method public int getUserId();
     method public void setAutofillOptions(@Nullable android.content.AutofillOptions);
     method public void setContentCaptureOptions(@Nullable android.content.ContentCaptureOptions);
+    method public void updateDeviceId(int);
     field public static final String ATTENTION_SERVICE = "attention";
     field public static final String CONTENT_CAPTURE_MANAGER_SERVICE = "content_capture";
     field public static final String DEVICE_IDLE_CONTROLLER = "deviceidle";

core/java/android/content/Context.java

@@ -7330,6 +7330,7 @@ public abstract class Context {
      * @see #createDeviceContext(int)
      * @hide
      */
+    @TestApi
     public void updateDeviceId(int deviceId) {
         throw new RuntimeException("Not implemented. Must override in a subclass.");
     }