Add InputFilter rust component as InputListener stage.

Test: TEST=libinputflinger_rs_test; m $TEST && $ANDROID_HOST_OUT/nativetest64/$TEST/$TEST
Bug: 294546335
Change-Id: I2731d45f141c12c1e61b794ee614690b0a121e28
diff --git a/libs/input/input_flags.aconfig b/libs/input/input_flags.aconfig
index 3672387..a807d82 100644
--- a/libs/input/input_flags.aconfig
+++ b/libs/input/input_flags.aconfig
@@ -62,3 +62,10 @@
   description: "Disable touch rejection when the stylus hovers the screen"
   bug: "301216095"
 }
+
+flag {
+  name: "enable_input_filter_rust_impl"
+  namespace: "input"
+  description: "Enable input filter rust implementation"
+  bug: "294546335"
+}