The wc-analytics/reports/orders and /wc-analytics/reports/orders/stats endpoints have inconsistent parameter names for filtering the customer type: customer_type vs customer.
This was affecting the Customer Type filter in the orders analytics, reported in issue woocommerce/woocommerce-admin#5803, where the component expects the parameter names to be the same. This is because it uses a parameter name based on the key in the filter configuration (customer_type).
To resolve this, this PR updates /wc-analytics/reports/orders/stats to accept both customer_type and customer as parameter names for this filter. The customer parameter has however been deprecated in its description to discourage usage.
Co-authored-by: Sam Seay <samueljseay@gmail.com>