Consider roaming when auto switch

- Always prefer HOME over Roaming + Roaming user enabled.
- Roaming + Roaming user disabled == no service.

Fix: 306488039
Test: manual fake roaming and confirm all combination of cases.
Test: daily test following
https://docs.google.com/spreadsheets/d/1fw_ONvemAFVHS7c4nLUv6rSQ8uINBQnYDWtMpV-M9yw/edit#gid=0
tracking with b/310043079

Change-Id: I4157a1c5cc09afb7e6bc64edbd2b99db584e5a1f
diff --git a/flags/data.aconfig b/flags/data.aconfig
index e65f8e4..b1f5ab1 100644
--- a/flags/data.aconfig
+++ b/flags/data.aconfig
@@ -1,6 +1,13 @@
 package: "com.android.internal.telephony.flags"
 
 flag {
+  name: "auto_switch_allow_roaming"
+  namespace: "telephony"
+  description: "Allow using roaming network as target if user allows it from settings."
+  bug: "306488039"
+}
+
+flag {
   name: "use_alarm_callback"
   namespace: "telephony"
   description: "Use alarm callback instead of broadcast."
@@ -69,4 +76,3 @@
   description: "notify data activity changed for slot id"
   bug: "309896936"
 }
-