fix(AIP-136): support response msg lint with resource singular name

[noahdietz]

The core::0136::response-message-name rule uses a heursitic to verify and account for the target resource type being the response type of the custom method (rather than a message type that aligns with the RPC name). It did this by checking for a name field with a resource_reference annotation and comparing the type there to the type of a google.api.resource annotation on the response to see if they matched. However, some AIPs recommend using a resource-singular-aligned field name in the request message e.g. the AIP-144 Add/Remove methods. So rather than AddAuthor, which returns a Book, checking for a name field, it will check for a book field as well and use that allow the custom method response type to be a Book rather than AddAuthorResponse.

This still prefers name if present in addition to a resource-singular-aligned field.

Internal bug http://b/424243407