[CTS] RestoreSessionHostSideTest failing consistently

The test app had a wrong build target type (java_library instead of
android_helper_app)

Bug: 135671077
Test: atest RestoreSessionHostSideTest
Change-Id: Ib5518bd07f3504f054e1ec3c9b6a7cd03eac294f
diff --git a/hostsidetests/backup/RestoreSessionTest/Android.bp b/hostsidetests/backup/RestoreSessionTest/Android.bp
index 29f6e59..d6cdeb9 100644
--- a/hostsidetests/backup/RestoreSessionTest/Android.bp
+++ b/hostsidetests/backup/RestoreSessionTest/Android.bp
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-java_library {
+android_test_helper_app {
     name: "CtsRestoreSessionApp",
     defaults: ["cts_defaults"],
     static_libs: [