Unit testing

[a-wei-william]

I fixed the error for chart_data_with_valid_request for ukwho, trisomy21, turner. I couldn't figure out the error in test_openapi_spec

[eatyourpeas]

Thanks the openapi error comes because the schema for chart-coordinates has now changed - it accepts an optional enum of 'six-centiles' or 'nine-centiles'. Although I have changed it and regenerated the openapi.json automatically, it still breaks. Might be a question for @pacharanero ....