VpnDialogs: add string description for translation.

<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">

    <!-- Dialog title to identify the request from a VPN application. [CHAR LIMIT=60] -->

    <string name="prompt"><xliff:g id="app">%s</xliff:g>

        attempts to create a VPN connection.

    </string>

    <!-- Dialog message to warn about the risk of using a VPN application. [CHAR LIMIT=NONE] -->

    <string name="warning">By proceeding, you are giving the application

        permission to intercept all network traffic.

        <b>Do NOT accept unless you trust the application.</b> Otherwise,

        software.

    </string>

    <!-- Checkbox label to accept the request from a VPN application. [CHAR LIMIT=60] -->

    <string name="accept">I trust this application.</string>

    <!-- Dialog title for built-in VPN. [CHAR LIMIT=40]  -->

    <string name="legacy_title">VPN is connected</string>

    <!-- Button label to configure the current VPN session. [CHAR LIMIT=20] -->

    <string name="configure">Configure</string>

    <!-- Button label to disconnect the current VPN session. [CHAR LIMIT=20] -->

    <string name="disconnect">Disconnect</string>

    <!-- Label for the name of the current VPN session. [CHAR LIMIT=20] -->

    <string name="session">Session:</string>

    <!-- Label for the duration of the current VPN session. [CHAR LIMIT=20] -->

    <string name="duration">Duration:</string>

    <!-- Label for the network usage of data transmitted over VPN. [CHAR LIMIT=20] -->

    <string name="data_transmitted">Sent:</string>

    <!-- Label for the network usage of data received over VPN. [CHAR LIMIT=20] -->

    <string name="data_received">Received:</string>

    <!-- Dummy string for a blank value. [CHAR LIMIT=40] -->

    <string name="blank_value">--</string>

    <!-- Formatted string for the network usage over VPN. [CHAR LIMIT=40] -->

    <string name="data_value_format">

        <xliff:g id="number">%1$s</xliff:g> bytes /

        <xliff:g id="number">%2$s</xliff:g> packets