check initialized Vote data

Active on mainnet-beta (epoch 159), testnet (epoch 168) and devnet (epoch 96).

Introduced in solana-labs/solana PR #15503.

Feature id 3ccR6QpxGYsAbWyfevEtBNGfWV4xBffxRj2tD6A9i39F.

Vortex

• Consensus leaderboard
• Fees leaderboard
• Validators
• Stake pools
• Decentralization
• Client versions
• Cluster status
• Governance
• Feature gates
• SIMDs
• Activity
• API and AI usage