Add a flag to control the exposure of VCN APIs for mainline migration

Bug: 369703242
Test: build
Flag: android.net.vcn.mainline_vcn_module_api
Change-Id: I728275a90b0dea8add60631e034ec081a07f23d7
diff --git a/core/java/android/net/vcn/flags.aconfig b/core/java/android/net/vcn/flags.aconfig
index 5b30624..2966e8a 100644
--- a/core/java/android/net/vcn/flags.aconfig
+++ b/core/java/android/net/vcn/flags.aconfig
@@ -10,6 +10,14 @@
 }
 
 flag {
+     name: "mainline_vcn_module_api"
+     namespace: "vcn"
+     description: "Expose APIs from VCN for mainline migration"
+     is_exported: true
+     bug: "376339506"
+}
+
+flag {
     name: "safe_mode_timeout_config"
     namespace: "vcn"
     description: "Feature flag for adjustable safe mode timeout"