Enable IPV4V6 for APN Yesss

The APN of (Austria) A1's Yesss brand supports IPv4+IPv6 for more than
a year already. Carrier is A1 which officially describes IPv6 support
there: https://www.a1community.net/mobiles-internet-a1-net-cube-316/alle-infos-ipv6-bei-a1-fuer-dein-mobiles-internet-252429

Change-Id: I51f33d4d940ee02f38326228dcbe5cc11a93c129

prebuilt/common/etc/apns-conf.xml

@@ -523,7 +523,7 @@
   <apn carrier="Orange Web" mcc="232" mnc="12" apn="orange.web" user="web" password="web" authtype="3" type="default,supl" />
   <apn carrier="Orange MMS" mcc="232" mnc="12" apn="orange.mms" proxy="" port="" mmsproxy="194.24.128.118" mmsport="8080" mmsc="http://mmsc.orange.at/mms/wapenc" user="mms" password="mms" authtype="3" type="mms" />
   <apn carrier="Orange Video" mcc="232" mnc="12" apn="orange.video" user="video" password="" authtype="3" type="default,supl" />
-  <apn carrier="Yesss" mcc="232" mnc="12" apn="webapn.at" type="default,supl" />
+  <apn carrier="Yesss" mcc="232" mnc="12" apn="webapn.at" type="default,supl" protocol="IPV4V6" roaming_protocol="IPV4V6" />
   <apn carrier="UPC Mobile" mcc="232" mnc="13" apn="internet.at.upcmobile.com" type="default,supl" />
   <apn carrier="spusu" mcc="232" mnc="17" apn="mass.at" type="default,supl" />
   <apn carrier="UBIQUISYS" mcc="234" mnc="01" apn="internet" proxy="" port="" user="" password="" mmsc="" mvno_type="spn" mvno_match_data="Vectone Mobile" type="default,supl,mms" />