Ignore finalization in minimum_request_epoch

[emhane]

This issue is closed with conclusion that finalization should be ignored when considering blobs. #3141

[emhane]

Maybe, this issue is also related to that parameter #3204 (thanks @realbigsean)

[djrtwo]

ByRoot method is a separate issue than the serving of blobs to some deep depth ByRange.

As noted in the phase 0 p2p spec for the BlocksByRoot request:

Clients MUST support requesting blocks since the latest finalized epoch.

ByRoot methods require more load/sophistication because they can requested in any order. Thus these are only specified as MUST be available in the time since finality.