Use ShufflingCache instead of EpochCache for shuffling data

[twoeths]

Problem description

as stated in #8650 once we move to native state transition we will not have EpochCache anymore

Solution description

remove below methods on EpochCache and switch to ShufflingCache instead following this pattern

lodestar/packages/beacon-node/src/api/impl/beacon/state/index.ts

Line 270 in a8c0c7a

const decisionRoot = stateCached.epochCtx.getShufflingDecisionRoot(epoch);

TLDR:

• get decision root hex from IBeaconStateView given an epoch
• use ShufflingCache to get a shuffling instead

the list includes:

• getIndexedAttestation
• getAttestingIndices
• getCommitteeAssignments
• getCommitteeAssignment
• getShufflingAtSlot
• getShufflingAtSlotOrNull
• getShufflingAtEpoch
• getShufflingAtEpochOrNull

Additional context

No response