require-service-call-response-declaration - should work for assignment besides variable declaration

examples are:

1. [slack thread](https://checkdigit.slack.com/archives/C0EFU0ELC/p1742419981968439)
2. occurrence in [serve-runtime PR](https://github.com/checkdigit/serve-runtime/blob/25015d37a62c27773dc6d1676a4d826d84c9a45c/src/service/global-ping.ts#L254)