Enable publish blobs after block by default

[tbenr]

I've been monitoring on holesky nodes with this enabled and seems not affect much on our high-upload-bandwidth nodes.
It should be worthy for low upload-bandwidth nodes, like home stakers building blocks locally.

Wait	average wait time
disabled	18.04 ms
enabled	23.48 ms

over last 2000 blocks produced on holesky

it doesn't go lower than a certain delay because we anyway spend time in blobs preparation while block publishing is already started. So we additionally wait (when enabled) only when the "time-to-first-peer-published-block" is higher.

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.

[mehdi-aouadi]

So is this to prioritise block publishing for low bandwidth nodes (when block and blobs publishing are done simultaneously, blobs could delay the block publishing by consuming bandwidth)?

[tbenr]

yes, this is essentially to wait initiating blobs publishing until we successfully published the block to at least one peer

[mehdi-aouadi]

LGTM
Makes sense since it doesn't badly affect high bandwidth node and helps the low bandwidth ones