Fix back gesture not being handled by BackAnimationController

Bug: 375342507
Flag: EXEMPT bugfix
Test: BackAnimationControllerTest
Test: Manual, i.e. verify that issue of back gesture touch events being sent to app is not reproducible with fix.
Change-Id: I45b46e5aca3bc42db2fbaf518f65061bb11062b4
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
index e4db7b6..dca9881 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
@@ -985,7 +985,6 @@
         ProtoLog.d(WM_SHELL_BACK_PREVIEW, "BackAnimationController: finishBackNavigation()");
         mActiveCallback = null;
         mApps = null;
-        mShouldStartOnNextMoveEvent = false;
         mOnBackStartDispatched = false;
         mThresholdCrossed = false;
         mPointersPilfered = false;