refactor: update command in JSON example to use placeholder for client password

- Replaced the hardcoded password in the command with a placeholder `{CLIENT_PASSWORD}` for improved security and flexibility.
- Ensured that the overall structure of the JSON remains unchanged while enhancing the example's usability.

evaluation_examples/examples/os/a462a795-fdc7-4b23-b689-e8b6df786b78.json

@@ -7,7 +7,7 @@
     {
       "type": "execute",
       "parameters": {
-        "command": "echo password | sudo -S su - charles",
+        "command": "echo {CLIENT_PASSWORD} | sudo -S su - charles",
         "shell": true
       }
     },