Remove dummy int64 field in protobuf format

[yunfengzhou-hub]

message.proto

message FileSystemTestMessage {
  // TODO: We have to add a dummy field with type int64 at the beginning,
  //  otherwise exception will be thrown.
  //  https://issues.apache.org/jira/browse/FLINK-31944

message AllTypesTest {
  // TODO: We have to add a dummy field with type int64 at the beginning,
  //  otherwise exception will be thrown.
  //  https://issues.apache.org/jira/browse/FLINK-31944