Add RestartExecutionsWithoutMessages to IFunctionStore

[stidsborg]

Summary

Adds a lighter variant of RestartExecutions — RestartExecutionsWithoutMessages — that restarts flows and returns their effects without fetching messages. Useful for restart paths that don't need the message snapshot, avoiding the extra message query/round-trip.

Changes

• New type StoredFlowWithEffects(StoredFlow, IReadOnlyList<StoredEffect>, IStorageSession) — StoredFlowWithEffectsAndMessages minus the Messages field.
• Interface IFunctionStore.RestartExecutionsWithoutMessages(IReadOnlyList<StoredId>, ReplicaId).
• Implementations with identical restart/ownership semantics, only the messages step removed:
  • InMemory — drops the MessageStore.GetMessages call.
  • PostgreSQL — 2 parallel queries (restart + effects) instead of 3.
  • MariaDB / SqlServer — effects come back inline from RestartFlowsAsync, so just the restart call.
  • Both CrashableFunctionStore decorators (test + sample) delegate the new method.

All stores reuse the existing private helpers — no new SQL.

Tests

Four store-level tests added to StoreCrudTests (template + overrides for all four stores): restart multiple unowned flows, skip already-owned flows, empty input, and includes-existing-effects (which also confirms messages aren't fetched, since the return type has no Messages field).

All 16 new tests pass across InMemory, PostgreSQL, MariaDB and SqlServer. Build is clean (0 warnings, 0 errors).

Note: this is an additive API change — RestartExecutionsWithoutMessages can't be a return-type overload of RestartExecutions, hence the explicit name.