[Bug]: Ancestry is never removed

[kamilsa]

Bug Summary

ancestry_ is never cleaned

Bug Description

SynchronizerImpl::ancestry_ field is an unordered_multimap.
It was observed that this container is constantly growing

Steps to Reproduce

Run KAGOME syncing node on any network, print the size of ancestry_ container

Effects of the Bug

Size of container is always growing

Expected Behavior

No response

System Information

anything

Additional Context

No response