Prop 493: Increase governance deposit: min_deposit to 150,000 AXL, expedited to 400,000 AXL

This proposal raises the deposit required to open a governance proposal on Axelar mainnet:

min_deposit: 2,000 AXL -> 150,000 AXL expedited_min_deposit: 3,000 AXL -> 400,000 AXL

All other governance parameters (voting period, quorum, thresholds, deposit ratio) are unchanged. The increase raises the economic cost of opening a proposal to deter low-effort and spam proposals, while keeping the deposit accessible to serious proposers. Deposits are returned when a proposal passes, or fails without being vetoed.