deprecate Eth1Data polling

[tersec]

• Don't track eth1_chain if in post-EIP-6110 period #7080

https://eips.ethereum.org/EIPS/eip-6110#eth1data-poll-deprecation

Consensus layer clients will be able to remove Eth1Data poll mechanism in an uncoordinated fashion once transition period is finished. The transition period is considered as finished when a network reaches the point where state.eth1_deposit_index == state.deposit_requests_start_index.

Before merging, ensure that all of these networks have achieved this condition:

• Chiado
• Gnosis mainnet (not possible before 2025-04-30)
• Holesky
• Sepolia
• Hoodi
• Ethereum mainnet (not possible before 2025-05-07)

[github-actions]

Unit Test Results

       15 files  ±0    2 630 suites  ±0   1h 15m 50s ⏱️ +43s
  6 372 tests  - 1    5 870 ✔️  - 1  502 💤 ±0  0 ❌ ±0 
44 281 runs   - 5  43 603 ✔️  - 5  678 💤 ±0  0 ❌ ±0 

Results for commit cea3ce7. ± Comparison against base commit 0e8e491.

♻️ This comment has been updated with latest results.