ACP-151: Use current block P-Chain height as context for state verification

[avalanche-foundation-admin]

Proposes that the ProposerVM passes inner VMs the P-Chain block height of the current block being built rather than the P-Chain block height of the parent block. Inner VMs use this P-Chain height for verifying aggregated signatures of Avalanche Interchain Messages (ICM). This will allow for a more reliable way to determine which validators should participate in signing the message, and remove unnecessary waiting periods.

https://github.com/avalanche-foundation/ACPs/tree/main/ACPs/151-use-current-block-pchain-height-as-context