Remove remove_input_channel_from_windowstate flag

This flag has been rolled out completely a while back.

Bug: 323450804
Flag: EXEMPT removing remove_input_channel_from_windowstate
Test: none
Change-Id: I724fea0a0fed846710b5dc119c9513e10e71112d
diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index fc859cb..e59eeb2 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -26,13 +26,6 @@
 }
 
 flag {
-  name: "remove_input_channel_from_windowstate"
-  namespace: "input"
-  description: "Do not store a copy of input channel inside WindowState."
-  bug: "323450804"
-}
-
-flag {
   name: "enable_input_event_tracing"
   namespace: "input"
   description: "Set to true to enable input event tracing, including always-on tracing on non-user builds"