Fix: bump kurtosis-cdk version and fix some unit tests

[googgoog]

This PR fixes multiple test flakiness issues without modifying production code:

• TTL Eviction Tests: Fixed by using cancellable contexts, creating proper subscriptions with TTL tracking;
• Datastream Runner Tests: Increased stop wait time from 200ms to 1500ms to account for async error handling with 1s internal sleep, and allowed expected bookmark errors in optimized mode;
• Connection Timeout: Added 100ms timeout to 18 tests using invalid URLs to prevent goroutine accumulation during repeated test runs;
• Concurrent Access Test: Redesigned from unsafe concurrent reset+access to safe phased approach (concurrent access → reset → repeat), eliminating sync.Once mutex violations;
• CI Infrastructure: Since the original image repository was deleted, upgrade kurtosis-cdk to v0.4.18 and free up disk space, as image building may fail due to insufficient space.