tethering: transitive deps from jni_libs

The build system collects transtive deps from jni_libs for APKs.
No need to list them explicitly in android_app definition.

Bug: 146992436
Test: m com.android.tethering
      deapexer extract com.android.tethering.apex apex
      unzip apex/priv-app/Tethering/Tethering.apk -u apk
      ls apk/lib/arm64-v8a

Change-Id: Icba6ea3611c443cbf22ad6363d0239377d16ac9e