Disallow Syncing From Genesis By Default

[ethDreamer]

Issue Addressed

• Disallow genesis sync by default #4377

This is WIP. Still needs:

• When povided the gensis sync flag, consider blocks that are from outside the prune window available if they are finalized
• During checkpoint sync backfill, always consider blobs from prior to the provided checkpoint available regardless of whether the flag is provided

[realbigsean]

When povided the gensis sync flag, consider blocks that are from outside the prune window available if they are finalized

I think after syncing to head, we no longer want to do this, even if we used genesis sync initially

[paulhauner]

I made an alternative to this over at #5038. I was originally just going to make a comment here, but I needed to code it to make sure I knew what I was talking about. We're also on a bit of a tight timeline for the Goerli Deneb release so I thought this might save some time. LMK what y'all think.

[realbigsean]

Closing in favor of #5038