Mark the test app as debuggable.

Accessing @TestApis is only allowed for
debuggable APKs on release builds.

Fixes: 181594072
Test: atest ./tests/cts/hostside/src/com/android/cts/net/HostsideRestrictBackgroundNetworkTests.java
Ignore-AOSP-First: Related CL http://ag/13615939 is not in AOSP yet.
Change-Id: I7777d70e3dc4217e7eb931060feb658d8943962a
diff --git a/tests/cts/hostside/app2/AndroidManifest.xml b/tests/cts/hostside/app2/AndroidManifest.xml
index 99b653c..4ac4bcb 100644
--- a/tests/cts/hostside/app2/AndroidManifest.xml
+++ b/tests/cts/hostside/app2/AndroidManifest.xml
@@ -36,7 +36,8 @@
      use to open sockets to remote hosts as a different user ID.
     -->
     <application android:usesCleartextTraffic="true"
-            android:testOnly="true">
+            android:testOnly="true"
+            android:debuggable="true">
 
         <activity android:name=".MyActivity"
              android:exported="true"/>