GET request with @online.route requires a body

[SalatielBairros]

Current problem

When I created an endpoint like:

@online.route("hello_world")
def hello_world():
    message = {
        'message': 'Hello World'
    }
    return message

And called it without body, the response was e 400 bad request:

This happens because the following line:

pyCarol/pycarol/app/online_api.py

Line 107 in 14cc9b7

local.request = OnlineRequest(values=flask_request.values, json=flask_request.json)

It calls flask.request.json():

If I add a body to the request, it works normally:

What's expected

When making a GET call to an endpoint, body should not be required.

[mergeable]

This issue should be labeled at least with kind and priority labels.