fix(framework) Suppress output when in JSON format for flwr ls

[chongshenng]

The flwr ls command raises a ValueError on this line if a run ID is not found. This won't be suppressed because the call to restore_output is made before the ValueError is raised. This PR fixes this for flwr ls.

To reproduce, run flwr ls 123 --format json before and after the fix.

➜ flwr ls --run-id 123 --format json
❌ Run ID 123 not found
{
  "success": false,
  "error-message": "Loading project configuration... \nSuccess\n Displaying information for run ID 123...\n\n"
}

and after:

➜ flwr ls --run-id 123 --format json
{
  "success": false,
  "error-message": "Loading project configuration... \nSuccess\n Displaying information for run ID 123...\n Run ID 123 not found\n\n"
}

[panh99]

LGTM!