add_filter( 'gettext', 'cyb_filter_gettext', 10, 3 );
function cyb_filter_gettext( $translated, $original, $domain ) {

    // Use the text string exactly as it is in the translation file
    if ( $translated == "None" ) {
        $translated = "View All";
    }

    return $translated;
}

function my_text_strings( $translated_text, $text, $domain ) {

    switch ( $translated_text ) {
        case 'None' :
            $translated_text = __( 'Choose all', 'my_theme' );
            break;
    }
    return $translated_text;
}
add_filter( 'gettext', 'my_text_strings', 20, 3 );