VerifyBlockJustification fails to assert ancestry of blocks not in the BlockTree

[EclesioMeloJunior]

Describe the bug

• While syncing Gossamer faces the following problem:

2023-11-30T13:58:45Z ERROR block data processing for block with hash 0xb9b61c899c864d69a20a2f3abad55825f51ff09b493100dce632033c12a27014 failed: checking if descendant of highest block: getting header: pebble: not found pkg=sync

• This problem happened after we changed the flow of importing blocks through sync (fix(dot/sync): verify justification before importing blocks #3576), basically, we only insert the block in the tree and execute it if its justification is valid otherwise we discard it.

• With this change, the function VerifyBlockJustification doesn't work properly because when it checks if a block belongs to the highest finalized chain. It requires that the block being verified is in the block tree, otherwise, it returns that cannot get the block header

• To fix this problem we should make sure that this function doesn't depend on blocks in the block tree and change it to verify blocks that were acquired through sync

[P1sar]

@EclesioMeloJunior please add issue that blocks this.

[P1sar]

@EclesioMeloJunior please remove duplicate #3468