Revert "Use mockito-extended in FrameworksNetTests"

This reverts commit 98b76cc2ec58396c804a4e4f658c915b3c80c138.

Reason for revert: <INSERT REASONING HERE>

b/190622577

Change-Id: Ief39f82875e6fa885829aea62eed00f2f2e6774e
diff --git a/tests/unit/AndroidManifest.xml b/tests/unit/AndroidManifest.xml
index 18653dc..d08b2f8 100644
--- a/tests/unit/AndroidManifest.xml
+++ b/tests/unit/AndroidManifest.xml
@@ -50,8 +50,7 @@
     <uses-permission android:name="android.permission.NETWORK_STATS_PROVIDER" />
     <uses-permission android:name="android.permission.CONTROL_OEM_PAID_NETWORK_PREFERENCE" />
 
-    <!-- Debuggable is necessary for mockito extended -->
-    <application android:debuggable="true">
+    <application>
         <uses-library android:name="android.test.runner" />
         <uses-library android:name="android.net.ipsec.ike" />
     </application>