Revert "Set down time when event slips into Wallpaper"

This reverts commit 9e2eb1f709fc78f8fdd231c25047fa511944ff01.

Reason for revert: Droidmonitor created revert due to breakages in b/357919724.

Change-Id: I51260eb42628e3d4fdd37ad41c24395217586806
diff --git a/services/inputflinger/dispatcher/TouchState.h b/services/inputflinger/dispatcher/TouchState.h
index 5a70dd5..9d4bb3d 100644
--- a/services/inputflinger/dispatcher/TouchState.h
+++ b/services/inputflinger/dispatcher/TouchState.h
@@ -47,7 +47,7 @@
             const sp<android::gui::WindowInfoHandle>& windowHandle,
             InputTarget::DispatchMode dispatchMode, ftl::Flags<InputTarget::Flags> targetFlags,
             DeviceId deviceId, const std::vector<PointerProperties>& touchingPointers,
-            std::optional<nsecs_t> firstDownTimeInTarget);
+            std::optional<nsecs_t> firstDownTimeInTarget = std::nullopt);
     void addHoveringPointerToWindow(const sp<android::gui::WindowInfoHandle>& windowHandle,
                                     DeviceId deviceId, const PointerProperties& pointer);
     void removeHoveringPointer(DeviceId deviceId, int32_t pointerId);