SystemUI: Expose VPN icon to allow toggling

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<vector xmlns:android="http://schemas.android.com/apk/res/android"

        android:width="24dp"

        android:height="24dp"

        android:viewportWidth="24.0"

        android:viewportHeight="24.0"

        android:tint="?android:attr/colorControlNormal">

    <path

        android:fillColor="@android:color/white"

        android:pathData="M12.09,9C11.11,7.5 9.43,6.5 7.5,6.5C4.46,6.5 2,8.96 2,12c0,3.04 2.46,5.5 5.5,5.5c1.93,0 3.61,-1 4.59,-2.5H14v3h6v-3h2V9H12.09zM20,13h-2v3h-2v-3h-5.16c-0.43,1.44 -1.76,2.5 -3.34,2.5C5.57,15.5 4,13.93 4,12c0,-1.93 1.57,-3.5 3.5,-3.5c1.58,0 2.9,1.06 3.34,2.5H20V13z"/>

    <path

        android:fillColor="@android:color/white"

        android:pathData="M7.5,12m-1.5,0a1.5,1.5 0,1 1,3 0a1.5,1.5 0,1 1,-3 0"/>

</vector>

    <!-- other weird signal stuff -->

    <com.android.systemui.tuner.StatusBarSwitch

        android:icon="@drawable/ic_statusbar_vpn"

        android:key="vpn"

        android:title="@string/legacy_vpn_name" />

    <com.android.systemui.tuner.BatteryPreference

        android:icon="@*android:drawable/ic_battery"

        android:title="@string/battery"