Chore!: Optimize snapshot unpausing

[izeigerman]

With introduction of the dev-only VDE mode, all snapshots that share the name also share the version. This means that fetching all snapshots with the same version may no longer be feasible, as it could result in retrieving the entire state in extreme cases.

This update optimizes the snapshot unpausing operation eliminating the need to fetch snapshots with shared versions. There were a few changes in the past that allow us to simplify the current implementation substantially:

• Deprecation of the Airflow support means that we no longer need to align the unpaused timestamp by the interval unit
• Interval compaction for garbage-collected snapshots means we no longer track intervals for individual snapshots, so there is no need to accurately reflect the effective-from timestamp in the state. Please note the effective-from timestamp is still considered when merging intervals for individual snapshots.