[examples][lock-common] Remove iostream include (#34952)

* iostream adds a lot of unnecessary functions when lock-app
   is compiled for non-linux platforms, increasing ram and
   flash consumption.
 * linux lock-app compiles without it

Signed-off-by: Andrei Menzopol <andrei.menzopol@nxp.com>

examples/lock-app/lock-common/src/LockManager.cpp

@@ -18,7 +18,6 @@
 
 #include "LockManager.h"
 
-#include <iostream>
 #include <lib/support/logging/CHIPLogging.h>
 #include <memory>