[ProjectTracking]: Fix the timing that block producer uses to wait for chunks

[robin-near]

Goals

Revisit and fix the t/6 timing used in Doomslug, in order to give chunk production and validation a fair share of the block production time, so that chunk misses can be minimized in the stateless validation setting.

Links to external documentations and discussions

https://near.zulipchat.com/#narrow/stream/407237-core.2Fstateless-validation/topic/Chunk.20t.2F6.20delay.20in.20Doomslug

Estimated effort

1 week of discussion, 1 week of implementation (highly depends on discussion result).

Assumptions

• None

Pre-requisites

• None

Out of scope

• Understanding why chunk misses happen beyond the scope of consensus.

[walnut-the-cat]

Maybe related to #10954