[CNVM] Resume snapshot deletion

[orouz]

Describe the bug

the CNVM pipeline has a final step that deletes the snapshot it creates:

cloudbeat/internal/vulnerability/worker.go

Line 145 in c0ef8db

f.cleaner.CleanSnapshots(ctx)

but if for some reason the context gets canceled, like on configuration changes, then the snapshot won't be deleted.

we need a mechanism to be able to resume deletion if it was not complete

To Reproduce
Steps to reproduce the behavior:

1. Deploy CNVM integration and agent
2. before the scanning is complete, change integration configuration or agent log level to trigger a re-config
3. monitor logs to see logs like this:

[elastic_agent.cloudbeat][error] NewVulnerabilityCleaner.CleanSnapshots: error deleting snapshot: snap-0b1e394cc735f9d13, error deleting snapshot snap-0b1e394cc735f9d13: operation error EC2: DeleteSnapshot, context canceled

Expected behavior

CNVM is able to delete snapshots even if cycle was inturpeted

Additional context

• there is an additional, different issue that also requires a stateful cycle that enables resuming workloads - Account for workloads exceeding cycle period #2180