Buildoor doesn't require `SignedBuilderRequestAuth` in `getExecutionPayloadBid` request body

[eth2353]

Was just looking into the Builder API spec and noticed Buildoor is not up-to-date with the latest spec which requires builders to return 400 if the SignedBuilderRequestAuth is not present in the request body on the getExecutionPayloadBid endpoint.

The SignedBuilderRequestAuth body is required. If the body is missing or malformed, the request is invalid and the builder MUST return a 400 response.

source

Buildoor currently returns 401 if the request body is missing, and it only returns 401 if the require_request_auth config value is true (defaults to false). Otherwise it silently ignores the missing body.