Fix electra light client types

[realbigsean]

Description

Noticed the EF SSZ tests were failing for some light client types. Looks like it's due to FINALIZED_ROOT_GINDEX, CURRENT_SYNC_COMMITTEE_GINDEX and NEXT_SYNC_COMMITTEE_GINDEX being updated, resulting in the lengths of fields in some types being updated

• LightClientUpdate
• LightClientFinalityUpdate
• LightClientBootstrap

This spec PR obviates the problem and makes more electra related updates:

https://github.com/ethereum/consensus-specs/pull/3811/files#diff-3c5f5d62f6d1d14d3324c9c37b025560ee9ccb335770a28f553ed374bc56e385R31

[michaelsproul]

With v1.5.0-alpha.5 I think we are unblocked on this. The changes required will be quite pervasive though, as the changing proof length requires many fixes.

Related spec PR:

• Update light client specifications for Electra ethereum/consensus-specs#3811

Related LH update:

• Implement Electra spec v1.5.0-alpha.5 #6305

[eserilev]

going to pick this one up

[michaelsproul]

Closing as completed in:

• Fix electra light client types #6361