Increase instruction data cost

[tao-stones]

Problem

Vote instruction deserialized size has been reduce by https://github.com/solana-labs/solana/pull/27565, could increase cost of instruction data size accordingly.

Proposed Solution

• reduce instruction byte-per-cu by 4 times (eg. increase instruction data cost by 4 times)

[tao-stones]

ig part of motivations to increase instruction data bytes cost is to prevent overpacking votes to a block. Probably worth to point out that instruction data bytes cost makes small portion of transaction cost. Vote instruction itself costs 2100 CUs, if its serialized data is 430 bytes, that'd add 430 bytes / 18 bytes-per-cu = 24 CUs, roughly 1% of instruction cost.