Update `tool.Invoke()` to return type `any` instead of `[]any`.
Toolbox return a map with the `results` key, and the SDK reads the
string from the key. So this won't break existing SDK implementation.
Fixes#870
`
tools:
wait_for_tool:
kind: wait-for
description: "Tool puts chat to sleep for given timeout example 3m,10s,
5m etc. For tasks such as cluster creation no need to wait. It takes
longer time such as 8m for instance creation. Use timeout value as
default if nothing is provided"
timeout: 10s
`
Output:
`
prernakakkar@prernakakkar:~/senseai/genai-toolbox$ curl -X POST -H
"Content-Type: application/json" -d '{"duration": "5m"}'
http://127.0.0.1:5000/api/tool/wa
it_for_tool/invoke
{"result":"[\"Wait for 5m0s completed successfully.\"]"}
`
