Remove DasLongPollCustody

[tbenr]

It has been designed when spec where different. Now, the sampler also cover the custody requirements too (it is a super set)

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.

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Note

Removes DasLongPollCustody (and its tests) and updates wiring to use DataColumnSidecarCustodyImpl directly in custody/by-root components.

• DAS Custody:
  • Remove DasLongPollCustody and its SlotEventsChannel subscription and timeout calculation.
  • Update BeaconChainController to use DataColumnSidecarCustodyImpl directly for DataColumnSidecarByRootCustodyImpl.
• Tests:
  • Delete DasLongPollCustodyTest and related stubs/usages.

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[zilm13]

LGTM