remove unused headers (#1544)

remove filesystem header file since it‘s never been used

Signed-off-by: uupks <[email protected]>

Author: uupks

rosbag2_storage_mcap/src/mcap_storage.cpp

@@ -39,7 +39,6 @@
 #include <mcap/mcap.hpp>
 
 #include <algorithm>
-#include <filesystem>
 #include <memory>
 #include <optional>
 #include <string>