refactor windows specific session, file transfer and waiting for image (#7184)

* refactor windows specific session, file transfer and waiting for image

1. File transfer doesn't show directory until correct session id is ensured
2. Fix file transfer, caused by `pi.username = self.lc.read().unwrap().get_username(&pi);` in `handle_peer_info` override empty username and `get_active_username` doesn't return currect session username
* Fix home directory not change when session changed, or wrong home directory
* Fix show empty remote directory rather than error messagbox when current session is in login screen
3. Show `Connected, waiting for image` after user choose the same
   session id

Signed-off-by: 21pages <pages21@163.com>

* update translations

Signed-off-by: 21pages <pages21@163.com>

* Update connection.rs

---------

Signed-off-by: 21pages <pages21@163.com>
Co-authored-by: RustDesk <71636191+rustdesk@users.noreply.github.com>

src/lang/et.rs

@@ -586,7 +586,7 @@ pub static ref T: std::collections::HashMap<&'static str, &'static str> =
         ("enter-2fa-title", ""),
         ("Email verification code must be 6 characters.", ""),
         ("2FA code must be 6 digits.", ""),
-        ("Multiple active user sessions found", ""),
-        ("Please select the user you want to connect to", ""),
+        ("Multiple Windows sessions found", ""),
+        ("Please select the session you want to connect to", ""),
     ].iter().cloned().collect();
 }