CHW-4601 SettingsValidation

settings payload failed validation; check field types and ranges against the endpoint documentation

Default message: settings payload failed validation; check field types and ranges against the endpoint documentation
HTTP status: 400 (client)

Problem. A settings PATCH body failed validation. Cause. The request was missing or unparseable JSON, contained a field outside its allowed range (e.g. exception_age not in 1..365), or supplied an invalid value (e.g. malformed block_contact_email). Fix. Inspect fields.field for the offending key, fix the value, and resubmit. The expected schema is documented inline in parseGeneralSettingsRequest. HTTP 400.