Set the container field of aconfig flags

Test: m
Bug: 312769710
Change-Id: Ie39de0e5115ecbd8ccc9bd294d0fcd678aae4244
diff --git a/flags/Android.bp b/flags/Android.bp
index 28aa750..f3e0c76 100644
--- a/flags/Android.bp
+++ b/flags/Android.bp
@@ -21,12 +21,13 @@
 aconfig_declarations {
     name: "iwlan_telephony_flags",
     package: "com.google.android.iwlan.flags",
+    container: "system",
     srcs: [
-      "main.aconfig",
+        "main.aconfig",
     ],
 }
 
 java_aconfig_library {
     name: "iwlan_telephony_flags_lib",
-    aconfig_declarations: "iwlan_telephony_flags"
+    aconfig_declarations: "iwlan_telephony_flags",
 }
diff --git a/flags/main.aconfig b/flags/main.aconfig
index 9bc80a1..795ffbd 100644
--- a/flags/main.aconfig
+++ b/flags/main.aconfig
@@ -1,4 +1,5 @@
 package: "com.google.android.iwlan.flags"
+container: "system"
 
 flag {
     name: "prevent_epdg_selection_threads_exhausted"