Set the container field of aconfig flags

Please see go/aconfig-flag-containers for more context

Test: m
Bug: 312769710

Change-Id: Ic0caabd55521274bcf48ec6d6aa44c6d53059bf3
diff --git a/camera/Android.bp b/camera/Android.bp
index 22f1633..4c5b160 100644
--- a/camera/Android.bp
+++ b/camera/Android.bp
@@ -46,6 +46,7 @@
 aconfig_declarations {
     name: "camera_platform_flags",
     package: "com.android.internal.camera.flags",
+    container: "system",
     srcs: ["camera_platform.aconfig"],
 }