[Meta] Middlewares have different HTTP response codes for auth errors

[jamietanna]

Looks like this should be aligned everywhere.

nethttp-middleware/oapi_validate.go

Lines 105 to 106 in ac41b59

	case *openapi3filter.SecurityRequirementsError:
	return http.StatusUnauthorized, err

https://github.com/oapi-codegen/echo-middleware/blob/bd401ffc8b5c352e067dc6a2bf2a47fcb6b4e2d2/oapi_validate.go#L174

[mromaszewicz]

IMO, every bug we hit where a hardcoded behavior is incorrect or inconsistent is an opportunity to allow the user to parameterize the response. I'll think about how to do this. We don't want to change existing behavior, but also we need to allow users to handle that error themselves.