Adds `future_git_tag_incompatible` to the `replica_sets_multiversion_gen` task tags in `etc/evergreen_yml_components/tasks/resmoke/server_divisions/durable_transactions_and_availability/tasks.yml`.

The `enterprise-rhel-8-64-bit-future-git-tag-multiversion` variant compiles the "latest" binary at FCV 100.0 (`bv_future_git_tag: r100.0.0-9999`). The `replica_sets_multiversion_gen` task generates `replica_sets_last_continuous` and `replica_sets_last_lts` suites, both of which use `useRandomBinVersionsWithinReplicaSet`. This assigns 9.0 ("last-continuous") or 8.0 ("last-lts") nodes to replicasets whose primary is running at FCV 100.0. Those older binaries fatal-assert during initial sync because `100.0` is not in their valid FCV set, causing 100% task-timeout failures (BF-43386).

The analogous `multiversion_gen` task (same file, line 1048) was already tagged `future_git_tag_incompatible` for this reason. `replica_sets_multiversion_gen` was missed. The failures were masked before SERVER-120949 because the future-tag compile was broken; once that fix landed the primary correctly compiled at 100.0, exposing the gap.

The variant's task selector `- name: .multiversion !.future_git_tag_incompatible` will automatically skip this task once it is tagged, with no other variants affected.