[Fix] Fix memory leak in fuzzy storage khash tables

[Fix] Fix memory leak in fuzzy storage khash tables

In init_fuzzy(), two khash tables were created but their destructors
were not added to the config mempool:
- ctx->default_forbidden_ids
- ctx->weak_ids

While these tables were destroyed in the worker cleanup code (before
exit), this cleanup doesn't run during configtest, causing a memory leak.

Fix: Add mempool destructors for both hash tables, similar to how
ctx->keys and ctx->errors_ips are handled. This ensures proper cleanup
in all scenarios including configtest.