We don't currently support unordered bulkWrite on mongos, but it is possible for the fuzzer to generate unordered bulkWrite invocations to run there that cause the server to crash, e.g. if the invocation generates a StaleConfig error and leads to the case we plan to handle in SERVER-76953 where we do not have a reply for every write.

We can add a uassert that checks only ordered bulkWrites are run on mongos for now to prevent further fuzzer failures until this behavior is properly supported.