don't reset the cursor image

...in internal calls to restore pointer focus. Necessary for the
unclutter patch, and there's no harm in avoiding this call even in
mainline; might prevents issues in same edge cases.

dwl.c

@@ -1490,7 +1490,7 @@ motionnotify(uint32_t time)
 	/* If there's no client surface under the cursor, set the cursor image to a
 	 * default. This is what makes the cursor image appear when you move it
 	 * off of a client or over its border. */
-	if (!surface)
+	if (!surface && time)
 		wlr_xcursor_manager_set_cursor_image(cursor_mgr,
 				"left_ptr", cursor);