reduce stake warmup cooldown from 25% to 9%

Active on mainnet-beta (epoch 565), testnet (epoch 586) and devnet (epoch 584).

Introduced in solana-labs/solana PR #32723.

Feature id GwtDQBghCTBgmX2cpEGNPxTEBUTQRaDMGTr5qychdGMj.

Vortex

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