Consider non-canonical chains when finding common ancestor

[VolodymyrBg]

PR Description

This PR enhances the findCommonAncestor method in ForkChoiceStrategy to consider non-canonical local chains when finding a common ancestor with a remote chain.
Previously, when comparing a remote chain to find a common ancestor, we only compared it with our canonical head. But if the chain we selected to sync is non-canonical for us, we might have a lot of blocks on that chain that we are not considering, thus we end up unnecessarily redownloading them.
The implementation now:
1.First tries to find a direct common ancestor between the two specific chains (using the original algorithm)
2.If no direct common ancestor is found or to find a better one, checks all local chain heads (including non-canonical ones)
3.Selects the common ancestor with the highest slot number to minimize the amount of data that needs to be redownloaded
A new test case was added to verify the correct behavior when dealing with non-canonical chains.

Fixed Issue(s)

fixes #9194

Documentation

• I thought about documentation and added the doc-change-required label to this PR if updates are required.

Changelog

• I thought about adding a changelog entry, and added one if I deemed necessary.