feat(web): shutdown placeholder method

This adds the `shutdown` method to `Session`.
The body is not yet implemented, but frontend code can be modified
to call it as of now.
Once the implementation is complete, no change on frontend code
will be required.

crates/web/src/session.rs

@@ -286,6 +286,11 @@ impl Session {
 
         Ok(())
     }
+
+    pub fn shutdown(&self) -> Result<(), IronRdpError> {
+        // TODO: https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpbcgr/27915739-8f77-487e-9927-55008af7fd68
+        Ok(())
+    }
 }
 
 fn build_config(username: String, password: String, domain: Option<String>) -> connector::Config {
@@ -414,7 +419,6 @@ where
 {
     use ironrdp::connector::Sequence as _;
     use x509_cert::der::Decode as _;
-    use x509_cert::der::Encode as _;
 
     #[derive(Clone, Copy, Debug)]
     pub struct RDCleanPathHint;
@@ -522,8 +526,8 @@ where
             .tbs_certificate
             .subject_public_key_info
             .subject_public_key
-            .to_der()
-            .context("subject public key DER encode")?;
+            .raw_bytes()
+            .to_owned();
 
         let should_upgrade = ironrdp_async::skip_connect_begin(connector);