Don't break key event stream when enabling a11y

Bug: 62862624
Test: Enable magnification, then enable TalkBack with the
a11y shortcut. Verify that volume keys work.
A11y service CTS, a11y units tests.

Change-Id: I729ab17d24f758b5ce534ffde43d2126a1f9536c
(cherry picked from commit 6b5cde5f256fe75acbfda1b447dc6230753700ca)
diff --git a/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java b/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
index 9e4d89c..0e42e6d 100644
--- a/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
+++ b/services/accessibility/java/com/android/server/accessibility/AccessibilityInputFilter.java
@@ -271,6 +271,7 @@
 
     private void processKeyEvent(EventStreamState state, KeyEvent event, int policyFlags) {
         if (!state.shouldProcessKeyEvent(event)) {
+            super.onInputEvent(event, policyFlags);
             return;
         }
         mEventHandler.onKeyEvent(event, policyFlags);