Remove DUN requirement for tethering

package com.android.networkstack.tethering;

import static android.content.Context.TELEPHONY_SERVICE;

import static android.net.ConnectivityManager.TYPE_ETHERNET;

import static android.net.ConnectivityManager.TYPE_MOBILE;

import static android.net.ConnectivityManager.TYPE_MOBILE_DUN;

import android.net.util.SharedLog;

import android.provider.DeviceConfig;

import android.telephony.SubscriptionManager;

import android.telephony.TelephonyManager;

import android.text.TextUtils;

import com.android.internal.annotations.VisibleForTesting;

    /** Check whether dun is required. */

    public static boolean checkDunRequired(Context ctx) {

        final TelephonyManager tm = (TelephonyManager) ctx.getSystemService(TELEPHONY_SERVICE);

        // TelephonyManager would uses the active data subscription, which should be the one used

        // by tethering.

        return (tm != null) ? tm.isTetheringApnRequired() : false;

        return false;

    }

    public int getOffloadPollInterval() {