Fix dont_skip_on_early_ro to be read only again

commit 4509966315ca9334d4637f8f364a34a12985ab13 accidently removed
the read only attribute from this flag.

Bug: 307674749
Bug: 273702768
Change-Id: I27ff11077226d5bc13731f4fd86dff0dc183ea47
diff --git a/services/surfaceflinger/surfaceflinger_flags.aconfig b/services/surfaceflinger/surfaceflinger_flags.aconfig
index c8f4218..eda0674 100644
--- a/services/surfaceflinger/surfaceflinger_flags.aconfig
+++ b/services/surfaceflinger/surfaceflinger_flags.aconfig
@@ -189,6 +189,10 @@
   namespace: "core_graphics"
   description: "This flag is guarding the behaviour where SurfaceFlinger is trying to opportunistically present a frame when the configuration change from late to early"
   bug: "273702768"
+  is_fixed_read_only: true
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
 }
 
 flag {