Check behavior of a server with just prompts.

Fixed bugs:
- empty tools lists should not be returned as 'null'

-- prompts --
code_review

-- client --
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "2024-11-05",
    "capabilities": {},
    "clientInfo": { "name": "ExampleClient", "version": "1.0.0" }
  }
}
{ "jsonrpc": "2.0", "id": 2, "method": "tools/list" }
{ "jsonrpc": "2.0", "id": 4, "method": "prompts/list" }
-- server --
{
	"jsonrpc": "2.0",
	"id": 1,
	"result": {
		"_meta": {},
		"capabilities": {
			"completions": {},
			"logging": {},
			"prompts": {
				"listChanged": true
			},
			"resources": {
				"listChanged": true
			},
			"tools": {
				"listChanged": true
			}
		},
		"protocolVersion": "2024-11-05",
		"serverInfo": {
			"name": "testServer",
			"version": "v1.0.0"
		}
	}
}
{
	"jsonrpc": "2.0",
	"id": 2,
	"result": {
		"_meta": {},
		"tools": []
	}
}
{
	"jsonrpc": "2.0",
	"id": 4,
	"result": {
		"_meta": {},
		"prompts": [
			{
				"arguments": [
					{
						"name": "Code",
						"required": true
					}
				],
				"description": "do a code review",
				"name": "code_review"
			}
		]
	}
}
