Update 17_186_mcp_cli_testing.html

[b4rdos]

Add initialisation step before calling mcp server.

Fixes issue

echo '{"jsonrpc":"2.0","method":"tools/list","id":1}' | python echo_server.py | jq
[09/29/25 17:22:27] WARNING  Failed to validate request: Received request before initialization was complete                  session.py:363
{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32602,
    "message": "Invalid request parameters",
    "data": ""
  }
}

[github-actions]

Validation Success