Revert^2 "Mark @FlaggedApi flags as exported"

5df163225b3f98912522994930804ba77bd80e62

Change-Id: I3d54d5235398831aec42b06e52300fa1adb515e2
diff --git a/flags/subscription.aconfig b/flags/subscription.aconfig
index aea9bd0..0522a3c 100644
--- a/flags/subscription.aconfig
+++ b/flags/subscription.aconfig
@@ -88,4 +88,5 @@
   namespace: "telephony"
   description: "Provide APIs to retrieve the status and recurrence rule info on a subscription plan"
   bug: "357272015"
+  is_exported: true
 }