samples: net: echo_server: Do not enable settings db for nsos

Enabling CONFIG_SETTINGS will just print error if built for nsos
so disable settings support it for that target.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

samples/net/sockets/echo_server/sample.yaml

@@ -141,6 +141,7 @@ tests:
       - native_sim/native/64
     extra_args:
       - EXTRA_CONF_FILE="overlay-nsos.conf"
+      - CONFIG_SETTINGS=n
     harness_config:
       type: multi_line
       ordered: false