Fix error code for unsupported_req error.

[jyao1]

Fix #2619

[steven-bellock]

libspdm/library/spdm_requester_lib/libspdm_req_encap_certificate.c

Lines 31 to 35 in d83ef43

	if (libspdm_get_connection_version(context) < SPDM_MESSAGE_VERSION_11) {
	return libspdm_generate_encap_error_response(
	context, SPDM_ERROR_CODE_UNSUPPORTED_REQUEST,
	0, response_size, response);
	}

code like this shouldn't even exist. Ie, if the negotiated version is 1.0 then libspdm_get_encap_response_certificate should never be called. I can file a separate issue for that.