Possible issue regarding CWD internal command.

[cirobruno]

Dear developer, good Afternoon.

First, thank you for sharing your library.

I'd like to contribute with an issue report.

I've been using your library for connecting an ESP32 to FileZilla and I've found an issue that possibly regard internal CWD command.

The context is an application written in PlatformIO, using FreeRTOS. The setup() function calls:
`
...

servidorFTP.addUser(FTP_user, FTP_psw);

// servidorFTP.setFilesystem(&SD);

// servidorFTP.setFilesystem(&SPIFFS);

servidorFTP.addFilesystem("SD", &SD);

servidorFTP.addFilesystem("SPIFFS", &SPIFFS);

servidorFTP.begin();

...
`

When connecting through FileZilla, connection and access to ESP32 look fine, like this:
`
New Connection from 192.168.5.107:58471

USER base

PASS dados

CWD /SD

TYPE I

PASV

500 Unknown command

PORT 192,168,5,107,228,140

MLSD
`

And I can access, for example, "/SD" folder

But then, when I try to access some subfolder, the command is received in ESP32 like that:
`
CWD /SD/Teste05

[E][vfs_api.cpp:64] open(): /sd/SD/Teste05 does not exist
`

And FileZilla reports that this directory doesn't exist:

Would this be a failure, or should I fix something in my code?
Thank you.
Regards, Ciro Bruno.