uk-who/chart-coordinates only works with height

[mbarton]

Anything else (weight, ofc or bmi) causes a validation exception:

growth-api-1  | 2024-07-10T19:27:51.142703424Z   {'type': 'missing', 'loc': ('response', 'centile_data', 1, 'uk_who_infant', 'female', 'height'), 'msg': 'Fiel
d required', 'input': {'weight':  [elided full centile data]

To reproduce:

curl -X POST -H 'Content-Type: application/json' -d '{"measurement_method":"weight","sex":"female","centile_format":"cole-nine-centiles","is_sds":false}' http://localhost:8000/uk-who/chart-coordinates