Open Stripe billing management (cancel, change card, invoices)
POST
bearerAuthheader
AuthorizationBearer <token>Mailly API key（Authorization: Bearer ）
Billing management URL
application/json- response
success*booleanurl*string[key: string]?unknowncurl -X POST 'https://api.mailly.site/billing/subscription/portal'{ "success": true, "url": "string", "property1": null, "property2": null}