Add in-memory causal ordering for task run recorder

[desertaxle]

Causal event ordering was removed from the task run recorder in #15244, which I firmly believe has led to the errors seen in #17767. Task run events may arrive out of order. While it's rare, with enough volume, out-of-order task run events become common and can lead to failed inserts and tasks appearing to stay in running if the COMPLETED races the initial event for a task and loses.

The original causal ordering implementation used the database for storage, which led to poor DB performance. This PR introduces an in-memory implementation of causal ordering to avoid DB performance degradation while getting the benefits of causal ordering for single-server setups.

For multi-server setups, a causal ordering implementation already exists in prefect-redis. We can add a mechanism to swap out the causal ordering implementation in a subsequent PR.

Closes #17767

[codspeed]

CodSpeed Performance Report

Merging #18634 will not alter performance

_{Comparing in-memory-causal-ordering (905d142) with main (e825a0f)}

Summary

✅ 2 untouched benchmarks

[zzstoatzz]

awesome! just a couple nits