Reduce web SSH session log spam (#49635)

Prevents emitting error log messages when users exit SSH web
sessions under normal circumstances.

Closes #49394

lib/web/terminal.go

@@ -875,7 +875,7 @@ func (t *TerminalHandler) streamTerminal(ctx context.Context, tc *client.Telepor
 		t.log.WithError(err).Error("Unable to send close event to web client.")
 	}
 
-	if err := t.stream.Close(); err != nil {
+	if err := t.stream.Close(); err != nil && !errors.Is(err, io.EOF) {
 		t.log.WithError(err).Error("Unable to close client web socket.")
 		return
 	}

lib/web/terminal/terminal.go

@@ -115,8 +115,8 @@ func (t *WSStream) WriteMessage(messageType int, data []byte) error {
 
 // WriteError displays an error in the terminal window.
 func (t *WSStream) WriteError(msg string) {
-	if _, writeErr := replacer.WriteString(t, msg); writeErr != nil {
-		t.log.WithError(writeErr).Warnf("Unable to send error to terminal: %v", msg)
+	if _, err := replacer.WriteString(t, msg); err != nil && !errors.Is(err, websocket.ErrCloseSent) {
+		t.log.WithError(err).Warnf("Unable to send error to terminal: %v", msg)
 	}
 }