RESTRICT AUTOMERGE: Camera: fix wrong signalStreamFlush call

Sometimes the waitUntilIdle call will finish without RequestThread
sending the signalStreamFlush call down to HAL.
Reset the flag when the wait finishes to avoid a wrong call fired
later when the request thread goes to paused.

Test: CTS on Pixel 3, partner testing
Bug: 162062652
Change-Id: I7c6674860a688f0bc42d4083793514b546cbd65d
diff --git a/services/camera/libcameraservice/device3/Camera3Device.h b/services/camera/libcameraservice/device3/Camera3Device.h
index 9b0648d..6b8601f 100644
--- a/services/camera/libcameraservice/device3/Camera3Device.h
+++ b/services/camera/libcameraservice/device3/Camera3Device.h
@@ -838,6 +838,7 @@
         }
 
         void signalPipelineDrain(const std::vector<int>& streamIds);
+        void resetPipelineDrain();
 
       protected: