[PIP-029] ULTRA Debt IR Increase from 4% to 6%+ for LRT Collateral

This proposal revises the Debt Interest Rate from 4% to 6.5% and mint fee from 0.75% to 1% for the new Prisma LRT troves.

Read: https://gov.prismafinance.com/t/pip-029-ultra-debt-ir-increase-from-4-to-6-for-lrt-collateral/144