SERVER-78253 allowed users to drop a hashed shard key index, and modified some assertions in shard_key_index_must_exist.js. However, this feature was not guarded by a feature flag, and so multiversion suites would fail the test due to differing behavior between 7.0 and 7.1. We added a binary version check in the test to ensure the test passes on regular and multiversion suites. Once last-lts becomes 8.0, we should remove the binary version check and only leave the 7.1 behavior tests.