Boolean parameters must be passed as lowercase strings (“true”/“false”) due to direct query param appending

[Raifa21]

Boolean parameters (like offline) need to be explicitly passed as lowercase strings "true" or "false" for them to work correctly. This seems to be due to how query parameters are appended in the generated code:

if local_var_params.get('offline') is not None:
    query_params.append(('offline', local_var_params['offline']))

(from friends_api) I've only confirmed this with the friends_api, but this should be the case for all boolean parameters.

Tested on 1.19.1.