Avoid accessing full beacon state in PrepareNextSlotScheduler

[twoeths]

Problem description

as part of #8650 we should not need the full beacon state in PrepareNextSlotScheduler

Solution description

right now we need a full CachedBeaconStateAllForks in PrepareNextSlotScheduler in order to:

• get payload attributes
  • get expected withdrawals
  • genesis time
  • epoch
  • randao mix
  • proposer index
  • latest execution payload header block hash
• slot, epoch
• randao mix
• compute and cache its root early

instead of that, we should create a beacon state view as stated here and consume it everywhere

Additional context

No response