fix(updatesite): Add org.slf4j pkg to fix serial monitor launch (#840)

Author: kolipakakondal

bundles/com.espressif.idf.terminal.connector.serial/META-INF/MANIFEST.MF

@@ -27,6 +27,7 @@ Export-Package: com.espressif.idf.terminal.connector.serial.activator;x-internal
  com.espressif.idf.terminal.connector.serial.controls,
  com.espressif.idf.terminal.connector.serial.launcher,
  com.espressif.idf.terminal.connector.serial.nls;x-internal:=true
+Import-Package: org.slf4j
 Bundle-ClassPath: .,
  lib/javax.websocket-client-api-1.1.jar,
  lib/Java-WebSocket-1.5.2.jar